Mushroom Fajitas

These Mushroom Fajitas are simple to prepare and can be on your dinner table in just 25 minutes! The mushrooms are seasoned with Mexican spices for a delicious flavor profile and are vegan and vegetarian. Serve these fajitas with your favorite toppings and enjoy!

Portobella mushroom fajitas cooked on a sheet pan.

If you’ve ever had fajitas before, you know why it’s a popular Mexican dish. A fajita is a Tex-Mex dish that generally consists of grilled meat, vegetables, and tortillas. The word “fajita” is derived from the Spanish word for skirt steak, which is the traditional cut of meat used for this dish.

Fajitas are traditionally made with meat, but these mushroom fajitas are a vegetarian and vegan option that is just as delicious!

The mushrooms give the dish a hearty texture and are full of flavor from the blend of Mexican-inspired spices. Simply season them, roast them in the oven until tender and flavorful, then add them to your favorite tortillas!

These easy portabello mushroom fajitas can be customized using many different toppings, but we love adding avocado, salsa, and lime juice.

Whether you’re vegan, vegetarian, or just looking for a delicious and easy mushroom recipe, these portobello fajitas are sure to be a family favorite!

Why You’ll Love This Recipe

  • The mushrooms add a hearty, rich texture even in the absence of meat.
  • You can cut the time down to just 25 minutes by prepping the peppers and onions in advance.
  • The topping possibilities are endless allowing you to customize the mushroom fajitas.
  • This dish uses simple and healthy ingredients you can find anywhere.

Ingredients You Need

All of the ingredients for portabella mushroom fajitas on a white countertop.
  • Limes – Use fresh lime juice for the best flavor.
  • Extra Virgin Olive Oil – You can substitute with avocado oil, if needed.
  • Spices – You need a mix of dried garlic power, dried onion powder, chili, cumin and salt to give these mushrooms a Mexican twist of flavor.
  • Bell Peppers – Use a mix of red, green and yellow bell peppers for a fresh garden taste that’s packed with nutrients. You can also use poblano peppers, if desired.
  • Red Onion – Use red onion for the best flavor. You can substitute with a yellow onion, if desired.
  • Portobello Mushrooms – Use large portobello mushrooms for these fajitas as they have the best texture and flavor.

How to Make Portobella Mushroom Fajitas

This recipe come together quickly and easily. Be sure to check out the prep-ahead tip to save time when cooking the mushroom fajitas.

Preparing the sauce and layering the bell peppers, onions and mushrooms on a sheet pan. before baking.
  1. Make the marinade: To a small bowl, combine the lime juice, olive oil, and dry seasonings until fully incorporated. Set aside.
  2. Coat the vegetables: Line a 12 x 16″ baking sheet with non-stick foil or a sheet of parchment paper. Preheat the oven to 400F. Add the chopped mushrooms and peppers to the prepared sheet pan. Pour the marinade on top and toss until all pieces are coated.
  3. Roast the vegetables: Roast for 10 minutes, then remove and toss carefully with tongs. Bake for an additional 10 minutes or until the mushrooms, peppers, and onions are cooked through and tender but not mushy.
  4. Garnish and serve: Remove from the oven and add to a bowl or serving dish. Add the filling to flour tortillas or corn tortillas and garnish with your favorite toppings!

PREP AHEAD (Save Time!) – To save even more time, use pre sliced peppers and onions or cut the peppers, onions and mushrooms in advance. This saves about 15 minutes of the total recipe time, so at dinnertime you can prep and cook the mushroom fajitas in 25 minutes or less!

Mushroom fajitas served in tortillas with sour cream and guacamole on top.

Expert Tips

  • Use portobello mushrooms for the best results. They are larger and have a more robust flavor.
  • Slice the mushrooms evenly. They should be thin and all roughly the same size so they cook evenly.
  • Use pre-made fajita or taco seasoning if you do not have all of the spices on hand.
  • Roasting time is dependent on how thick you cut your vegetables and how hot your oven gets. Start with 10 minutes and check periodically until desired texture is reached.

Serving Suggestions

  • Make these easy mushroom fajitas gluten free by using your favorite gluten-free tortillas.
  • Serve the vegetarian fajitas on a bed of brown rice or quinoa for a heartier meal.
  • Top with avocado, salsa, lime juice, black beans, fresh cilantro and sour cream for a delicious and satisfying meal.
  • Serve veggie fajitas with a side of flavorful Mexican Corn on the Cob or Mexican Black Beans.
  • Stuff this mushroom filling into tacos, burritos or enchiladas for a fun twist on classic dishes.
  • Make this dish suitable for a low carb or keto diet by serving over a bed of lettuce or roasted veggies.
Mushroom fajitas served over tortillas.

Other Mexican Inspired Recipes

Did you make these portobello Mushroom Fajitas? Leave a recipe rating and review below.

Portobella mushroom fajitas cooked on a sheet pan.

Mushroom Fajitas

Yield: 6
Prep Time: 20 minutes
Cook Time: 20 minutes
Total Time: 40 minutes
These portabella mushroom fajitas come together easily in less than 40 minutes!
5 from 2 votes


  • 2 limes, freshly juiced
  • 1 tablespoon extra virgin olive oil
  • 1 teaspoon garlic powder
  • 1 teaspoon onion powder
  • 1 teaspoon salt
  • 1/2 teaspoon chili powder
  • 1/2 teaspoon cumin powder
  • 12 ounces portabella mushrooms, with the stems removed and the tops sliced
  • 1 green bell pepper, deseeded and sliced
  • 1 red bell pepper, deseeded and sliced
  • 1 yellow bell pepper, deseeded and sliced
  • 1 large red onion, sliced


  • Preheat the oven to 400 degrees Fahrenheit and line a 12×16 inch baking pan with foil.
  • Whisk the lime juice, olive oil, garlic powder, onion powder, salt, chili powder and cumin together in a small bowl then set aside.
  • Add the mushrooms, peppers and onions to a prepared baking pan then pour the sauce on top and toss to combine.
  • Bake for 10 minutes and toss then bake for 10 more minutes or until the peppers and onions are soft to your liking.
  • Serve with tortillas, sour cream, guacamole, lime wedges and freshly minced cilantro for garnish, if desired.


Nutritional information does not include any additional toppings. 
Storing: Leftover mushroom fajitas can be stored in an airtight container in the fridge for up to four days. Because the vegetables contain a high amount of water, freezing is not recommended as they will become too mushy when thawed.
Reheating: To reheat leftovers, simply add them to a skillet over medium heat until warmed through. You can also reheat them in the microwave, but be careful not to overcook or they will become mushy.


Calories: 45kcal, Carbohydrates: 5g, Protein: 2g, Fat: 3g, Saturated Fat: 1g, Polyunsaturated Fat: 1g, Monounsaturated Fat: 2g, Trans Fat: 1g, Sodium: 397mg, Potassium: 250mg, Fiber: 1g, Sugar: 2g, Vitamin A: 68IU, Vitamin C: 2mg, Calcium: 10mg, Iron: 1mg
Course: Dinner
Cuisine: American, Mexican
Author: Ashley C.
If you try this recipe, don’t forget to leave a review below or share a photo and tag @spoonfulofflavor on Instagram.

2 comments on “Mushroom Fajitas”

  1. This was excellent. My friends who are vegetarian came over for dinner so I thought I would make this. Everyone really enjoyed it. Will definitely be making this again.

  2. Always looking for new ideas for Meatless Monday – this was perfect! So good!

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