Sheet Pan Vegetarian Fajitas

5 from 2 votes

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Portobello mushrooms take the place of meat or chicken in these vegetarian fajitas with a colorful mix of bell peppers. They quickly marinate in chili powder, cumin and other dried spices and lime juice before they roast in the oven. No skillet required. This is a 30-minute dinner that should make it into your weeknight rotation no matter the season.

Five vegetarian fajitas arranged on an oval plate.

Why You’ll Love This Fajita Recipe

Everyone can use a convenient sheet pan meal. Let the oven do the work and roast all the veggies together on a baking sheet. This reduces the amount of active time involved in making the recipe, and it simplifies cleanup.

It’s great for meal planning and leftovers. You can rewarm the peppers, onions and mushrooms in the microwave. They will taste just as great as when you originally roasted them, so you can get multiple meals out of this recipe depending on how many people you are serving.

This is a nutritious vegetarian recipe with a lot of vegetables. The bell peppers, portobello mushrooms and onions are seasoned in variety of dried spices in the marinade before they cook in the oven.

What are Fajitas?

When you’re at a restaurant, you usually hear this Tex-Mex favorite before you see it. That’s because fajitas are traditionally sautéed in cast iron skillets and brought to the table sizzling. Marinated skirt steak, chicken or shrimp are cooked with bell peppers and onions that are cut into strips.

Fajitas are served with tortillas, sour cream, guacamole, pico de gallo, salsa, tomatoes and beans on the side. Then you assemble them at the table.

The Ingredients

Ingredients including, peppeps, onion, portobello mushrooms, beans, cilantro, lime, tortillas and cheese.

This is what you need:

  • Portobello mushrooms are great because they have big caps that you can slice and add to the other veggies. They have good flavor and do a wonderful job roasting too. 
  • Bell peppers: I like to go with every color of the rainbow using red, yellow, orange and green peppers for these fajitas. You can stick with one or use a mix depending on looks and taste. I know some people like red peppers best.
  • Onions: My preference is red onions for this recipe, but you can use white onions instead.
  • Spices: The marinade has a blend of chili powder, cumin, garlic powder, onion powder, paprika, oregano, salt and black pepper.
  • Lime juice adds fresh citrus flavor to the marinade. I also serve the fajitas with lime wedges on the side.
  • Olive oil is the base for the marinade. By stirring the dried seasonings into oil, they more evenly coat all the vegetables.
  • Black beans: For some protein, I serve the fajitas with beans that I like to add in when I am doing assembly. Before that, I toss the beans in the remaining marinade, treating it kind of like a sauce. You can swap them for pinto beans.
  • Tortillas: Make sure to warm either corn or flour tortillas before you enjoy your fajitas.
  • Avocado: I take a ripe avocado and mash it with a fork in a small bowl. Then I spoon a little bit of it into each fajita. You can use guacamole too.
  • Fresh cilantro, cotija cheese and yogurt or sour cream are all things you can use to garnish your fajitas.

How To Make Vegetarian Fajitas

Preheat the oven to 400 degrees F. Line 2 sheet pans with parchment paper.

1. Make the marinade. Whisk the chili powder, cumin, garlic powder, onion powder, paprika, oregano, salt, pepper, lime juice and olive oil in a bowl that’s big enough to hold all the veggies.

2. Stir the peppers, onions and mushrooms into the marinade. I like to use my hands to toss everything around, so the veggies make full contact with the marinade.

Fajita marinade in a bowl. Vegetables stirred into marinade.

3. Spread the sliced vegetables across both baking sheets. Leave the extra marinade in the bowl.

4. Roast the peppers, onions and mushrooms for 20 minutes until they are lightly browned at the edges. It’s a good idea to rotate the pans about halfway through roasting.

Fajita vegetables on a sheet pan before and after they are roasted.

5. Stir the black beans in the leftover marinade in the bowl.

6. Serve the fajita vegetables with warmed tortillas, black beans, mashed avocado, cilantro, cheese and yogurt or sour cream.

Beans stirred into marinade in a bowl. Fajita vegetables, tortillas, mashed avocado, cheese, cilantro and yogurt in individual bowls ready for assembling.

Serving Vegetarian Fajitas

Fajitas should be served so that everyone can make their own rather than already assembled. I put the vegetables in a big dish and then spoon everything to go with them in their own individual bowls. For a side dish, try my Quinoa Black Bean Salad, Roasted Corn Salad or Mango Avocado Salad.

And remember that you can skip the tortillas to create fajita bowls with cilantro lime rice. I will even chop leftover peppers, mushrooms and onions and put them in a salad too.

Leftovers & Storage

You can store leftovers in an airtight container in the fridge up to 4 days. Keep the fajita vegetables separate from the beans and toppings. Warm the veggies in the microwave.


Can you turn these into fajita bowls? 

Absolutely! You don’t have to serve the vegetables with tortillas. Put them in a bowl with cilantro lime rice, black beans and the rest of the accompaniments.

How can you make these vegan fajitas?

The roasted fajita vegetables on their own are vegan. Either skip cheese and sour cream for toppings or use plant-based versions.

What’s the best way to warm tortillas?

If you have a gas stove, you can put a tortilla straight on the grates over a low flame for a few seconds to get a little char. Use tongs to flip it over to the other side. To warm up to 5 tortillas in the microwave, stack them up and wrap them in a damp paper towel and zap them in 30-second blasts.

More Sheet Pan Recipes

Kung Pao Tofu 
Sheet Pan Gnocchi and Vegetables
Honey Garlic Tofu with Broccoli
Sesame Tofu Asparagus
Roasted Mediterranean Vegetables and Halloumi
Teriyaki Tofu Broccolini

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Sheet Vegetarian Fajitas

5 from 2 votes
Prep: 10 minutes
Cook: 25 minutes
Total: 35 minutes
Servings: 6 Serves 6
Ready in 30 minutes, portobello mushrooms, bell peppers and onions roast on sheet pans in the oven for these simple vegetarian fajitas.


  • 1 teaspoon chili powder
  • 1 teaspoon cumin
  • 1/2 teaspoon garlic powder
  • 1/2 teaspoon onion powder
  • 1/2 teaspoon paprika
  • 1/2 teaspoon oregano
  • 1 teaspoon kosher salt
  • 1/2 teaspoon black pepper
  • Juice of 1 lime
  • 1/4 cup olive oil
  • 4 bell peppers sliced 1/4-inch wide
  • 1 medium red onion sliced 1/4-inch wide
  • 4-5 portobello mushrooms about 12 ounces, sliced 1/2-inch wide
  • 1-15 ounce can black beans drained and rinsed
  • Flour or corn tortillas warmed before serving
  • 1 avocado mashed
  • Chopped cilantro cotija cheese and yogurt or sour cream for serving


  • Preheat the oven to 400 degrees F. Line 2 baking sheets with parchment paper.
  • To make the marinade, whisk together the chili powder, cumin, garlic powder, onion powder, paprika, oregano, salt, pepper, lime juice and olive oil in a large bowl.
  • Stir the peppers, onions and mushrooms into the marinade. Make sure they are all well coated.
  • Spread the marinated veggies across both sheet pans, leaving the excess marinade in the bowl.
  • Roast for 20 minutes until they are lightly browned at the edges, rotating the pans halfway through roasting.
  • Stir the black beans in the remaining marinade in the bowl.
  • Serve the fajita vegetables with warm tortillas, black beans, mashed avocado, cilantro, cheese and yogurt.


Pinto beans can be used instead of black beans.
You can use a shredded Mexican cheese blend instead of Cotija cheese.
To make vegan fajitas, do not serve them with yogurt, sour cream or cheese or use plant-based versions.
Store leftovers in an airtight container in the refrigerator up to 4 days. Keep the fajita vegetables separate from the beans and toppings. Warm the mushrooms, peppers and onions in the microwave.


Calories: 368kcal | Carbohydrates: 45g | Protein: 11g | Fat: 18g | Saturated Fat: 3g | Polyunsaturated Fat: 3g | Monounsaturated Fat: 11g | Trans Fat: 0.002g | Sodium: 972mg | Potassium: 866mg | Fiber: 12g | Sugar: 7g | Vitamin A: 2730IU | Vitamin C: 111mg | Calcium: 109mg | Iron: 4mg

Nutrition information is automatically calculated, so should only be used as an approximation.

Additional Info

Course: Main Dishes
Cuisine: Tex-Mex
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Hi, I'm Paige.

Welcome to Last Ingredient where you will find simple seasonal recipes with plenty of fruits and vegetables, all for the home cook.

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