Vegetarian portobello mushroom fajitas are a simple and crowd-pleasing dinner! They’re cooked on a sheet pan with the peppers and onions to speed things up and make clean-up a breeze. Great for a weeknight!
Make the marinade by adding soy sauce, vinegar, 2 tablespoons of the oil and spices to a small jar. Cover tightly and shake until thoroughly combined.
Prep portobello mushrooms: remove stems, clean out the gills with a spoon, and wipe the top of the cap clean with a damp towel. Cut into 1/2″ slices and add to a medium bowl, then pour the marinade over the top and toss to coat. Let sit at least 10 minutes.
Meanwhile, slice bell pepper and red onion and add to sheet pan. Toss with the remaining tablespoon of oil and season with salt and pepper. Once mushrooms are done marinating, add to sheet pan. Transfer to oven and cook for 20 minutes.
To assemble, add mushrooms, bell peppers and onions to a tortilla and add your favorite toppings.