Sheet Pan Portobello Fajitas

$10.81 recipe / $2.70 serving
by Beth Moncel
4.83 from 34 votes
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I got that craving for fajitas the other day and just had to have ’em. I decided to switch things up a bit from my usual sheet pan fajitas and use portobello caps in place of the chicken. I also added a little smoky chipotle powder to the spice mix to keep things interesting. These Sheet Pan Portobello Fajitas are a new and welcome twist on the classic. A little squeeze of lime on top and a slice or two of creamy avocado, and you have a really tasty veggie-filled dinner.

Three Portobello Fajitas on a plate.

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Portobello Mushrooms on a Budget

Portobello mushrooms aren’t the cheapest item in the produce aisle, so it’s important to use some of our budget byting principles here. First, make sure you compare prices both between available grocery stores and even within the store. If your grocery store sells them both packaged together and loose, be careful to compare the per-pound price because it might be cheaper to buy them loose! 

Second, we’re going to combine the portobello mushrooms with other ingredients that are much less expensive, like onions, bell peppers, and tortillas to balance out the total price and keep the price per serving on the low side. 

Make it Spicy or Mild

The recipe, as written below, is a little smoky and spicy thanks to the chipotle powder in the fajita spice mix. If you prefer a mild fajita, skip the chipotle powder and make sure to use a chili powder blend that is mild. If you want your fajitas to be smoky but not spicy, replace the chipotle powder with smoked paprika. 

Meal Prep It!

The filling for the fajitas works great as a meal prep. Just pack up the roasted mushroom, pepper, and onion mix in a lunch container with a slice of lime and a couple of tortillas. When it’s time for lunch, remove the tortillas and lime, reheat, then fill the tortillas, squeeze your lime, and enjoy!

For the avocado, I suggest slicing a few slices off the whole avocado each day. Only the exposed surface will darken, and it only darkens slightly (it doesn’t turn completely black like mashed avocado). The darkening of the avocado does not mean it is spoiled, it just means that it has been exposed to oxygen (like a brown apple), and is still perfectly safe to eat.

What to Serve with Portobello Fajitas

Sweet Corn Salsa or Summer Sweet Corn Salad would be a wonderfully light and fresh contrast to these portobello fajitas. And if you want to dress them up a little bit more you could whip up a quick batch of Guacamole or Pico de Gallo

Roasted portobello and vegetables on a sheet pan.
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Sheet Pan Portobello Fajitas

4.83 from 34 votes
Sheet Pan Portobello Fajitas are an easy and flavorful vegetarian dinner idea that all cooks on one pan for easy cleanup!
Author: Beth Moncel
Three portobello fajitas on a plate.
Servings 4 (two fajitas each)
Prep 15 minutes
Cook 40 minutes
Total 55 minutes

Ingredients

FAJITA SPICE MIX

  • 1 Tbsp chili powder* ($0.30)
  • 1/2 tsp chipotle powder ($0.05)
  • 1/2 tsp onion powder ($0.05)
  • 1 tsp cumin ($0.10)
  • 1/2 tsp garlic powder ($0.05)
  • 1 tsp sugar** ($0.05)
  • 1/2 tsp salt ($0.03)

FAJITAS

  • 2 portobello mushroom caps ($3.99)
  • 2 bell peppers (any color) ($2.29)
  • 2 yellow onions ($0.64)
  • 3 Tbsp olive oil ($0.38)
  • 8 small flour tortillas (6-inch) ($1.00)
  • 1 avocado ($1.09)
  • handful cilantro (optional) ($0.25)
  • 1 fresh lime ($0.59)
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Instructions 

  • Preheat the oven to 400ºF. In a small bowl, stir together all the ingredients for the fajita spice mix
  • Slice the portobellos, bell peppers, and onions into 1/4 inch wide strips. Place the sliced vegetables on a large sheet pan. Drizzle the olive oil over the vegetables then sprinkle the fajita spice mix over top. Use your hands to toss the vegetables until everything is well coated in oil and spices.
  • Roast the vegetables in the fully preheated oven for 40 minutes, or until the vegetables are slightly wilted and the edges have a nice brown color. Stir the vegetables half way through the roasting time to make sure everything gets even exposure to the hot air.
  • After removing the vegetables from the oven, squeeze fresh lime juice over top. Sprinkle chopped cilantro over the vegetables. To serve the fajitas, scoop a small amount of the roasted vegetables into each tortilla and add a slice of avocado.

See how we calculate recipe costs here.


Equipment

  • Enamelware Sheet Pan

Notes

*The chili powder I use is a mild blend made by McCormick. It is not spicy at all and contains barely any salt. If using a different brand, make sure to adjust the salt and/or chipotle accordingly.
**The small amount of sugar in this recipe helps caramelize the vegetables and give everything that grilled or charred flavor that is characteristic of fajitas.

Nutrition

Serving: 1ServingCalories: 423kcalCarbohydrates: 49gProtein: 9gFat: 23gSodium: 782mgFiber: 9g
Read our full nutrition disclaimer here.
Have you tried this recipe?Mention @budgetbytes or tag #budgetbytes on Instagram!
side view of three portobello fajitas on a plate.

How to Make Sheet Pan Portobello Fajitas – Step by Step Photos

Fajita spices in a wooden bowl.

Begin by preheating the oven to 400ºF. In a small bowl, stir together 1 Tbsp chili powder, 1/2 tsp chipotle powder, 1/2 tsp onion powder, 1/2 tsp garlic powder, 1 tsp cumin, 1 tsp sugar, and 1/2 tsp salt. 

Whole vegetables on a cutting board.

I used 8 oz. portobello caps (2-3 depending on their size), two bell peppers (any color), and two yellow onions for my fajitas.

Sliced vegetables on a baking sheet.

Slice the vegetables into strips about ¼-inch wide. I also cut the portobello strips in half, so the pieces aren’t quite so large. Place the sliced vegetables on a large sheet pan.

Spices being sprinkled over the sliced vegetables.

Drizzle 3 Tbsp olive oil over the vegetables, then sprinkle the prepared fajita seasoning over top.

Seasoned vegetables ready to roast.

Use your hands to toss the vegetables in the oil and spices until everything is evenly coated, then make sure the vegetables are spread out over the baking sheet in an even layer.

Roasted vegetables on the sheet pan.

Roast the vegetables in the preheated oven for 40 minutes, or until they are slightly wilted and have browned on the edges. Stir the vegetables halfway through the roasting time to make sure everything gets even exposure to the hot air. 

Finished fajita vegetables on the baking sheet with lime and cilantro.

After roasting, squeeze lime juice over the vegetables and top with chopped cilantro.

Three portobello fajitas on a plate.

To serve, scoop a small amount of the fajita vegetables into each small tortilla and add a slice of fresh avocado.

Overhead view of the fajita vegetables on a sheet pan.

Seriously, these Chipotle Portobello Oven Fajitas are probably one of my favorite vegan recipes!

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  1. Every Thursday I make myself a new (to me) vegan or vegetarian recipe for lunch. If I think its delicious, I add it into my rotation for my non vegetarian family to enjoy too. I made this for my lunch today and I can not WAIT to make it for everyone this weekend. Holy cow is this delicious! It’s super easy to put together too. I think even my mushroom hating husband is going to like this one!

  2. This is a great recipe! I also used these fajita veggies in burrito bowls, no matter what it’s it’s always easy, and very tasty. The whole family likes it and I love that it’s vegetarian and the sodium level can be controlled by making your own seasoning!

  3. So delicious! I divided the peppers into a separate baking sheet than the onion and portobellos. The portobello sheet didn’t take as long to cook as the peppers, so I’m glad I did that. But it turned out so yummy. Definitely making this again.

  4. This works even in a deep skillet on the stovetop. And the fajita spice mix tastes great, even without the chipotle or salt!

  5. Love the Vegan Portobello Fajitas!! Delicious and brilliant!! Thanks again!! Love, Yung Kush

  6. Made exactly as is and I really liked it, husband said it was just okay- no issues with it being soggy or wet.

    I did I have to divide it between two half sheet pans since I don’t have any full sheets and only needed to be cooked for 30 min.

    I felt it could have used more mushroom in the ratio and will definitely add more next time. Will become part of our regular rotation.

  7. Easy, healthy, and more filling than I anticipated. My grocery store had sliced portabellas for the same price as full caps, so that made my life even easier. So don’t assume sliced will cost more!

  8. Just had these for dinner tonight and these will be on repeat at our home. I went a little over time with 40 mins in our oven. They got slightly charred but yummy nevertheless. Next time I will do only 30 mins and they will be perfect. We had these with all the fixings (guacamole, tomatillo salsa, pickled hot green chiles, homemade yogurt dip and topped with some chili lime chili hula) Hubbby and Kiddo added their fav. Meats but I gobbled my taco up as is. This receipt is so delicious and hands free that it is a perfect busy weeknight dinner. Next time I will bake a big batch for meal prep. Thanks Beth!! 

  9. Rather than spreading all the sliced vegetables on the baking sheet, why not toss in a bowl or ziplock bag with the oil and spices, and then put on the baking sheet. Seems more logical to me!

  10. Just a question in general not necessarily related to this recipe. When you post that a recipe is updated, what gets changed? Just the pricing or the process and ingredients, too?

    1. Hi Julie, We re-test the recipe and make any changes we feel are necessary to make it even better. We also photograph it again and update ingredients and pricing. XOXO -Monti

  11. This recipe was phenomenal. My husband is a huge meat eater and even he loved this and said he prefers these over the steak fajitas from our local Mexican restaurant. I made a few minor changes, mostly because we have a 1 year old daughter who eats what we eat and I didn’t want it to be too spicy for her. So I reduced the chili powder to 2 tsp and used smoked paprika instead of chipotle powder. My only regret is that my avocados were not ripe LOL

  12. If you follow it exactly as written out in the recipe, they are wonderful! I did not have an issue with sogginess or anything really. This is such an easy, delicious meal! It also feels really wholesome.

  13. I’m not the biggest fan of portobello mushrooms and also wanted to get a little more protein into this recipe. So I subbed a mock meat (Quorn beef strips) for the mushrooms and it was great! Simple but flavorful approach to fajitas that really hit the spot. (FYI I did exclude onion due to an allergy.)

  14. I never review much, but I have to comment how good these are. My family thought we would miss the meat, but we didn’t. Using the little bit of sugar with the spices to mimic the pan-fried caramelization is brilliant! It makes preparing fajitas so much easier. Cutting the vegetables 1/4 inch as noted and using large lined sheet pans seems to give us the best results as it allows plenty of room to let liquid evaporate and a ton of flavorful caramelization to occur. I even double the recipe across two sheet pans to make sure we have leftovers. Everyone just snarfs this stuff up! This is a regular in our household now.

  15. Mine ended up very soggy and not browned like I would have wanted. Makes for very drippy tacos. Still, the flavor is good. I served it with corn, pan fried potatoes, and refried beans. Definitely good for a meal, not so much for meal prep because they are so soggy.

  16. Just want to say that we make this ALL the time because it’s so easy and so good! It’s perfect as-written, but oftentimes we end up making it with just peppers (just depends on what we have on-hand), but love how adaptable it is. We tend to always try to have peppers in the fridge since we know that about once a week we’ll feel like making this recipe!

  17. !So good!! I’ve been looking for more plant based recipes and this is awesome ! I will be eating this all of the time!

  18. I love this recipe! In fact, I prefer it over the chicken fajitas. I also add sour cream to the tortilla and it is delicious!

  19. Great flavors, nice combination of textures. The roasted peppers and mushroom caps blend well. This is going to be my new favorite

  20. We made this recipe for dinner tonight – SO GOOD! We had four ‘bello caps to use up and cooked them all. Some shrimp might be tasty with this as well. Thank you!

  21. Thank you so much. I have all of the ingredients except the portobellos. I am going to make this today with the hopes that it will still taste as delicious as you’ve made it look here. Thanks!

  22. Hey Beth! I was thinking of suprising an Vegan friend with this recipe, it looks like a great/easy to make recipe, I am just wondering if you have something good to substitute out the Peppers for?

    Cheers from Sweden

    1. Hmmm, I don’t really know what you could use in their place. Peppers are a main part of the classic fajita filling, so it wouldn’t quite be the same without them. Technically you could do just about any vegetable, it just wouldn’t be very fajita-like. :)

  23. These were rediculously good. The chipotle chili powder really made all the difference. This will definitely enter our regular meal rotation – but we’ll probably add at least one more portabella mushroom. Thanks for another excellent recipe!

    1. This one won’t be quite as good if it has been frozen and thawed. The vegetables will probably get a bit watery, which is not what you want with fajitas. :(

  24. We love this recipe. It’s on frequent rotation in my house. We usually only get 3 servings because we can’t stop picking at the roasting pan, but who cares? More veggies, right? Thanks, Beth, for yet another winner.

  25. This was a great recipe! I really liked it with some avocado and sour cream. Yummy yummy! Would love to see a recipe for a portobello mushroom burger one day :) Thanks for all your great recipes! Your site has been 70-80% of my diet for the past year. :)

  26. These were so yummy and easy! The leftover veggies were even more delicious the next day and were easily repurposed into quesadillas. I am making these again and looking forward to making burrito bowls with the leftovers.

  27. I’m planning on making these tonight. They look really good and I’ve been looking for a way to try portobello mushrooms in a different way – this looks really good!

    Tell me, do you think I could sub out the spice mixture for taco seasoning? I don’t have chipotle powder or garlic powder, but I do have seasoning. I’ll just add in the sugar and salt with it. Do you think that would work?

    Thanks again for all your posts – they’re wonderful!

  28. These are so ridiculously good! Probably our favorite from your site so far (and that’s saying a lot, as we’ve been meal planning and eating pretty much off your site alone for the last 6 months).

    DELISH. Thank you!

  29. I love this recipe! I’m a huge fajita fan and I’m vegetarian. Thanks so much. Made it twice now.

  30. You use garlic powder in the step by step but not the simple recipe. Im assuming it was forgotten.
    Love the website!!!

  31. I could kiss you. I made this recipe this afternoon. I just ate it. It was so easy and so tasty. I used chicken thighs ( on sale) and portobellos ( loose, cheaper by the oz) and a HEB ( Texas chain of grocery store) Grill Masters, chipotle and garlic seasoning mix it was on sale for a DOLLAR and had all the ingredients in your spice mix minus sugar and cornstarch, Plus onion powder. So compared to the 7.00 bottle of chipotle powder I went with that. I can’t wait to make this again, for dinner, during the week lunches, or parties. THANK YOU ! I did add a tiny tiny bit of honey to one to make up for there not sugar. Both turned out nicely, I also used red peppers so thats probably why it didn’t need any sugar.

  32. I was hesitant to try this recipe because I’m not a huge fan of mushrooms, but it was delicious. I highly recommend it.

  33. Oh. My. God. I have sworn by your recipes for probably about 3 years now, I own your book, and I’m CONSTANTLY telling people that I love this blog. That having been said, I think this is my favorite Budget Bytes recipe yet! I didn’t have Chipotle spice, so I used Cayenne instead, which was still delicious. Thank you for helping me trick my family into thinking I’m a good and creative cook for all of these years!

  34. Omg.. Made these the other night and they were amazing!! Instead of dried chipolte seasoning I had a can of chipoltes in adobo and I used the sauce they come in along with some dried spices to season. Used the leftovers in quesadillas the following night. Definitely a keeper! Thanks, Beth, for sharing all your awesome ideas!

  35. I made this up the other night when I had a couple bell peppers I needed to use. Hubby wasn’t too keen on it at first since there was no meat. But he ate half the pan! He even said that with the big thick mushrooms he didn’t feel like he was eatting a vegan meal. And after running the recipe through my calorie app it turns out to be less then 100 calories per serving before adding the tortillas. That was a win for me!

  36. Great with the additions of mushrooms and chipotle. I thought it was perfectly seasoned and spicy, my kid disagreed.

  37. The original recipe ( which I make a lot!) uses cornstarch in the spice mix to help it thicken. Does this not need any?

  38. Did you find these loose mushroom caps at Rouses? If so I must not be looking hard enough!

    1. Yep! The one in mid-city, too. :) They’re usually on the bottom shelf of the mushroom area. This time, though, they were the last couple of caps in the bin, so hopefully they’re not going to stop selling them that way!

      1. Thanks – will have to check the one by me out on Airline. I really hope they still have them loose, I bring my own reusable produce bags so they would be perfect for this. I (very unfortunately) left MidCity 2 moves ago. Still my favorite neighborhood! :)

      2. It’s still my favorite neighborhood, too. :) There is a Rouse’s less than 2 blocks from my new place, but still go to the Mid-city location. LOL

  39. These look amazing! I’ve made a veggie roast like this before for gyros, but I never thought to add sugar to it to increase the caramelization . I’ll have to try that!

    Thanks!

  40. Another trick to save money on mushrooms is to use crimini mushrooms instead of portobellas. Crimini mushrooms aren’t as strong in flavor as portabellas but have more flavor than white/button mushrooms. Criminis are usually cheaper than portabellas and not much mpre than white.

  41. Beth – my mouth is watering – another good (and easy) recipe for me. You rock!

  42. These look unbelievably good! And great tip on checking prices of prepackaged vs. per pound. I need to remember that more often.