Last week I saw an amazing photo of an incredible slow cooker French dip sandwich recipe and I couldn’t stop thinking about them. I wanted those sandwiches and I wanted them bad. But then I thought, “What if I tried to make vegetarian French dip sandwiches?” and then I was on a mission. This portobello mushroom-based French dip recipe turned out really amazing on the first try. So amazing, in fact, that this is the most enthusiastic that I’ve seen my boyfriend about any recipe that I’ve made for him so far. And I feed him a lot. ;)
What is a French Dip Sandwich?
French dip sandwiches are made with tender shaved beef piled onto a French roll, topped with melted cheese (sometimes) and served with a rich broth, or au jus, for dipping. It’s absolutely delightful. BUT, because beef is so expensive these days, these vegetarian French dip sandwiches made with portobello mushrooms are a really tasty alternative. You won’t belive how delicious this broth is!
And what recipe had me drooling at my computer screen and ultimately inspired the vegetarian version? These Slow Cooker French Dip Sandwiches from Carlsbad Cravings.
How to Make a French Dip Sandwich Vegetarian
I replaced the tender beef in classic French Dip sandwiches with meaty strips of portobello mushrooms and sautéed onions to bulk them up while keeping the price low.
I’d normally add a little Worcestershire to the broth of a beef French dip, but that has anchovies in it. So, to mimic the salty-sweetness of Worcestershire, I added a little soy sauce and just a smidge of brown sugar. That hint of sweetness from the brown sugar really helped balance the flavors and made the broth complex, so don’t be tempted to skip it.
Also, I highly suggest using Better Than Bouillon to make your broth. It has a deep flavor and just the right amount of salt.
How to Store Leftovers
If you’re not eating these sandwiches all at once, store the mushroom and onions in the broth and reheat them together before piling the filling into the sandwiches and dipping them into the remaining broth. You can heat these sandwiches in a matter of minutes under the broiler, so it’s a nice quick meal for leftovers!
What Kind of Bread Should I Use?
One last note. Due to pricing and product availability, I did not use a French loaf for my sandwiches (I know, I know). Instead, I bought a pack of hoagie rolls that worked quite well. The key to choosing your bread for these sandwiches is to make sure you have something very sturdy and crusty so that it holds up to dipping in the delicious broth.
Vegetarian French Dip Sandwiches
Servings 4Ingredients
- 1 yellow onion ($0.32)
- 3 portobello mushroom caps (about ½ lb.) ($3.99)
- 2 Tbsp butter ($0.20)
- 1/8 tsp salt ($0.01)
- 1/8 tsp freshly cracked black pepper ($0.01)
- 1/4 tsp dried thyme ($0.02)
- 1/4 tsp dried oregano ($0.02)
- 2 cups vegetable broth* ($0.26)
- 1 Tbsp soy sauce ($0.06)
- 1/2 Tbsp brown sugar ($0.02)
- 1/8 tsp garlic powder ($0.01)
- 4 6-inch French or Hoagie rolls ($1.66)
- 4 slices provolone ($1.00)
Instructions
- Slice the onion into thin strips. Rinse the portobello caps to remove any dirt or debris. Slice each cap in half, then crosswise into 1/4-inch thick strips.
- Add the butter to a deep skillet along with the sliced onions. Sauté the onions over medium heat for a few minutes, or just until they begin to soften.
- Add the sliced mushrooms to the skillet along with the salt, pepper, thyme, and oregano. Sauté the mushrooms until they release all their moisture and the liquid in the bottom of the skillet has evaporated (about 10 minutes). You should see some browned bits coating the bottom of the skillet.
- Add the vegetable broth, soy sauce, brown sugar, and garlic powder and stir to dissolve the browned bits from the bottom of the skillet. Allow the liquid to come up to a simmer, then turn down to low and simmer for about 5 minutes while you toast the bread.
- Open the rolls and place them on a baking sheet, open sides up. Turn the oven on to broil and place the rolls in the oven on the middle rack. Watch the rolls closely and broil just until you see a slightly browning on the edges (about 5 minutes).
- Use a slotted spoon or tongs to take the mushrooms and onions out of the au jus. Divide the mushrooms and onions among the four rolls. Top each sandwich with a slice of provolone.
- Return the sandwiches to the oven and broil for a few minutes more, or just until the cheese is melted. Close the sandwiches up and serve with the au jus from the skillet for dipping.
See how we calculate recipe costs here.
Equipment
Notes
Nutrition
Have you tried this recipe?Mention @budgetbytes or tag #budgetbytes on Instagram!Video
How to Make Vegetarian French Dip Sandwiches – Step by Step Photos
Slice one yellow onion into thin strips. Wash and slice three portobello caps. I used three caps, which weighed ½ lb. total. I like to slice them in half, then crosswise into strips so that the strips aren’t super long.
Add the onions and 2 Tbsp butter to a deep skillet. Sauté the onions over medium heat just until they begin to soften (about 3 minutes).
Then add the sliced mushrooms, a pinch of salt and pepper, 1/4 tsp dried oregano, and 1/4 tsp dried thyme. Sauté the mushrooms and onions until the mushrooms release all their moisture and the liquid in the bottom of the skillet evaporates. There should be some caramelized browned bits stuck to the bottom of the skillet.
Add 2 cups of vegetable broth to the skillet and stir to dissolve the browned bits off the bottom. Then add 1 Tbsp soy sauce, 1/2 Tbsp brown sugar, and 1/8 tsp garlic powder.
Let the au jus come up to a simmer, then turn it down to low and let it simmer for 5-10 minutes while you toast the bread.
Place four opened French or hoagie rolls on a baking sheet, open side up. Turn the oven on to broil and toast the bread under the broiler just until you start to see a little browning on the edges. I kept my oven rack in the middle so that the bread was far enough away from the broiler that it wouldn’t toast super fast. That gives you a little more room for error.
Use tongs or a slotted spoon to pick the mushrooms and onions up out of the au jus, then pile them onto the toasted rolls.
Add a slice of provolone to each…
Then return the sandwiches to the broiler to melt the cheese. The open bread will continue to brown here, so if your bread was a little more on the brown side after the first broil, flip the pieces over so they’ll brown on top instead.
Finally, close up the sandwiches and serve while hot! But don’t forget to ladle that yummy au jus into little bowls for dipping.
These Vegetarian French Dip Sandwiches are seriously good stuff. nomnomnom
O……M…….G!!!!!! I made these tonight and wow what a winner! My husband adored them. They are so delicious and satisfying! I have enjoyed so many french dip ( classic style with beef) in my life and these are just as delicious! We are trying not to eat meat as much and with meals like this I won’t miss the meat at all! Thanks for this lovely recipe. :)
Looks delicious. Can’t wait to try it! I’m a longtime vegetarian and have found that Chinese black vinegar is an ideal vegetarian worcestershire sauce substitute. It’s available at Chinese markets, and I consider it an essential part of my vegetarian pantry.
Great tip! I’ll definitely be picking up some Chinese black vinegar. :-)
Made these last night they were great! However didnt have any brown sugar, so i added a little coke to it and it was perfect. i made regular french dips also for my family and that recipe called for coke so i just went ahead and added it to this was great.
Hi Beth!
Long time reader, first time commenter. I had to break my internet silence to tell you just how good these were. I typically hate mushrooms–it’s a texture thing, and I would love to get over it. My wife LOVES them, and would probably eat them with every meal if possible. I’ve been wanting to make these sandwiches for her since you posted the recipe, and I finally bit the bullet and made them this week. They were a hit! I knew she would love them, but I was shocked that I did too. The mushrooms had such a meaty and satisfying texture and the au jus was absolutely awesome. I’ve been following your blog for about three years now, and over that time I’ve incorporated countless ingredients into my pantry that I would never have tried otherwise. Your recipes have really changed the way that I eat and given me so much confidence as a home cook. I can’t thank you enough! It’s about time I wrote in to tell you. Keep up the great work!
Thank you!! I’m so glad that you liked them! This is seriously one of my favorite recipes, so it’s awesome to know that even a non-mushroom person thinks they’re good. ;)
These were a hit for Lunch at the fire station
I love this recipe! This is one of those things that as a vegetarian, there are just some things that you think you will never be able to enjoy the taste of again…but then i tried VEGETARIAN french dip sandwiches and I have been proven wrong!
Side note: I always use the leftovers to eat over egg noodles!!
Oh my GOSH these are good! I hadn’t had a French dip since I went vegetarian, but these are better than I remember them ever being. :) I used smoked gouda on mine, and I recommend it if anyone wants a cheese variation.
I don’t feel right only giving these only 5 stars, they deserve 10000000 haha
I have made about 75% of the recipes of Budget Bytes and I think there is only 1 recipe I haven’t loved but this is hands down my absolute favorite one I have made!!!
The changes I made in case anyone has dietary restrictions like us….I made my own GF buns, used vegan margarine instead of butter & vegan cheese and used beef broth instead of vegetable just because that’s what I had. Oh and I used mini Bella mushrooms instead because they were cheaper.
Definitely making this very often!
thanks so much for this very delicious recipe. I had to veganize it and it was wonderful! Used my own veggie broth, vegan butter & Follow Your Heart mozzarella cheese slices.. OMG it was SOOOOOO good. Have made twice now, so very satisfying. I was craving a french dip sandwich and this is the ticket. A little soy sauce and a dash or two of vinegar works great to make the veg sauce “beefy” .
How many calories per sandwich?
Annie’s brand makes a vegetarian Worcestershire sauce for future reference. :)
Thanks for the tip!!
These are amazing!! Im a newer vegetarian, a little less than a year, and Ive been missing meat like crazy recently! But this just fixed that completely! I used veggie broth with beef flavored (but vegetarian) bouillon and it tasted just like au jus. Im also celiac and these can easily be made gluten free. Fantastic recipe, thanks!
I’m a vegetarian and I’ve found some Worchestershire sauces that use hydrolyzed vegetable protein and non-animal sourced natural flavors instead of anchovies (Kroger’s house brand is one example).
This dish is so delicious. I crave it often! Leftovers are … just.. wow! Go ahead and make this dish. You won’t be disappointed.
We made these last night and they were marvelous! I love French Dip sandwiches with the juicy au jus but rarely eat meat these days. The meaty mushrooms were a perfect alternative. My meat-loving boyfriend put roast beef on his and we were both more than satisfied with the savory sauce, crusty ciabatta and melty provolone. We’ll be putting this meal into the normal rotation. Thank you!