This vegetarian mushroom Philly "cheesesteak" is made with sauteed mushrooms and peppers and topped with caramelized onions. This sub takes just over 30 minutes to make and is perfect as a quick dinner or sliced into sliders for an appetizer.
This is one of my favorite recipes. The mushrooms in this "cheesesteak" are BURSTING with umami flavor. Mushrooms are a great meat replacement for vegetarian cooking because they're a little chewy and packed with savory umami flavor. These little fungi are full of vitamins and minerals, making them a nutritious sandwich stuffer.
This quick weeknight recipe can be thrown together in just over 30 minutes. If you're looking for an easy appetizer, you can cut the sub in halves or thirds and share as mushroom sliders at a Superbowl party.
This post contains Amazon affiliate links. As an Amazon Associate I earn from qualifying purchases; read my disclaimer policy for more information.
As if savory mushrooms and peppers on a sub roll weren't good enough, there's another ingredient to get excited about: caramelized onions!
The sweetness of caramelized onions really pulls the sub together. You can make the caramelized onions in ~45 minutes to an hour. It depends on how caramelized you want them to be. I think waiting the few extra minutes is totally worth it, but if you're short on time you easily can speed up the process.
Here's what's in this vegetarian mushroom cheesesteak
- Sliced white and baby bella mushrooms sauteed in soy sauce and oregano. You can also use sliced portobello mushrooms or Cremini mushrooms here.
- Julienned red and green bell peppers
- Melted provolone cheese or you can easily make this recipe vegan by using vegan cheese
- Sweet golden brown caramelized onions
How to make caramelized onions
- Slice 2 large white onions into thin strips. In a large skillet, heat one tablespoon of oil over medium heat. Sprinkle the onions with a bit of salt and saute for 10 minutes, until lightly browned.
- After the onions have browned slightly, reduce the heat to medium-low and let the onions work their magic. Stir the onions every 7-10 minutes to prevent them from sticking.
- To speed up the cooking process and add sweetness you can sprinkle the onions with ~½ teaspoon of sugar.
- If the onions are drying out, splash them with a teaspoon of water.
The onions are ready when they're sweet and golden brown.
I love to serve these with chips and vegan french onion dip. If you're like me and can't get enough of mushrooms, check out these mushroom-centered recipes:
- Savory Vegan Mushroom Gravy
- Mushroom and Lentil Casserole
- Vegan Tater Tot and Green Bean Casserole
- BBQ Pulled Portobello Tacos
- Vegetarian Chili Mac
I hope you enjoy this savory sandwich.
Vegetarian Mushroom Cheesesteak with Caramelized Onions
- 2 tablespoons olive oil divided
- 2 large onions white, yellow, and red all work; 3 small onions
- ½ teaspoon salt
- 16 ounces baby bella or white mushrooms thickly sliced
- 1 red bell pepper, sliced sliced
- 1 green bell pepper sliced
- 1 tablespoon soy sauce
- 1 tablespoon all-purpose flour
- 1 teaspoon dry oregano
- 4 6" sub rolls
- 4 slices provolone cheese
- To make the caramelized onions: In a large skillet, heat 1 tablespoon olive oil over medium-high heat. Saute the sliced onions for 6-8 minutes, until lightly browned. Sprinkle with ½ teaspoon salt and lower the heat to medium-low. Stir the onions only every 9-10 minutes. They're ready when golden brown and sweet, which can take up to an hour.
- In a medium skillet, heat 1 tablespoon of olive oil over medium-high heat. Add the mushrooms and peppers and saute until the mushrooms release most of their juices, about 7-8 minutes.
- Sprinkle mushrooms with soy sauce and oregano. To thicken the mushrooms and their juices, sprinkle with 1 tablespoon of flour, stirring to brown.
- Melt the provolone cheese by placing each slice over a section of mushrooms and peppers. Cover the pan with a lid to melt.
- Scoop the melted cheese and mushrooms onto a toasted sub roll. Top with caramelized onions and enjoy!
- Leftovers and reheating: Store leftovers refrigerated in a closed container. Best within 3-4 days. Reheat in the microwave in just 1-2 minutes, or reheat on the stove-top over medium heat.
- Toasting the buns: Spread the buns with melted butter and garlic salt and toast at 350F for 3-4 minutes. This is the method that I use for meatball subs.
Did you make this recipe?
Tag @cozypeachkitchen on Instagram and hashtag
Very good! Substituted Worcestershire for soy to knock down the salt. Put the filled roll (less onions) in the broiler to met cheese. Next time will mix the onions thru to get everything in one bite. Will make again!
Thank you for the review! 🙂
My new favorite dish! Skipped the soy sauce due to BP issues but used several other spices. Awesome addition to my WFPB lifestyle. Yummy!
Thanks for the review, so glad you liked it! 🙂
OMG the best sub every thank you so so much yummy!!!
So glad you enjoyed it!! Thank you 🙂
Delicious! Added a little pepper jack for some kick.
Sounds like a delicious addition!
Made this for camping two weeks ago and we are making it again this week!! Sooo delicious!
Cassidy Reeser, RDN, LD
Sounds like such a fun camping meal! Thank you 🙂
Made this yesterday and it came out great! skipped the soy sauce and flour and cooked everything in one pan but it still tasted great! Will definitely make again!
Cassidy Reeser, RDN, LD
Thanks Mel! Glad you enjoyed it 🙂