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Portobello Mushroom Fajitas

April 18, 2024

A healthy, fast, vegetarian dinner is as easy and delicious as can be—meet our veggie-loaded portobello mushroom fajitas!


vegan Portobello Mushroom Fajitas on a sheet pan with tortillas

Vegan Fajitas? Vegan Fajitas!

Portobello mushrooms make a fantastic “meaty” vegetarian substitute for the traditional chicken or beef in these simple, flavorful fajitas. A dip in a lime-y marinade gives the mushrooms an extra kick of flavor, and bright bell peppers and onions add layers of texture to the finished mushroom fajitas. Top the finished fajitas with generous dollops of homemade guacamole, and indulge guiltlessly. Meatless Monday has never tasted better!

ingredients laid out for vegan fajitas, portobello mushrooms, bell peppers, onions, cilantro and tortillas
fajita sauce for vegan mushroom fajitas
vegan Portobello Mushroom Fajitas on a sheet pan
vegan Portobello Mushroom Fajitas with bell peppers on a sheet pan

Hit That Produce Aisle!

This healthy fajita recipe is really simple, and almost every ingredient comes from the produce aisle of the store—don’t you love that? It always makes us feel super virtuous to have a rainbow of produce in our grocery cart (virtual, or otherwise). And it should! Portobello mushrooms are seriously healthy—they’re a good source of copper, potassium, magnesium, zinc and even some B vitamins. If they were grown in sunlight or exposed to ultraviolet light—and many portobello mushrooms are—they can also be a good source of vitamin D.

In addition to some flour tortillas and taco seasoning, all you’ll need to make these mushroom fajitas is:

  • Portobello mushrooms (P.S. did you know that “portabella” and “portobello” are two different names for the same mushroom? We’re calling them portobellos, but the terms are interchangeable.)
  • Limes
  • Red onions
  • Bell peppers (We usually grab one of each color, to make things interesting.)
  • Cilantro

And for the guacamole (which is a must!) you’ll need:

  • Jalapeño
  • Avocados
  • Garlic
vegan Portobello Mushroom Fajitas on a sheet pan

How To Make Vegetarian Fajitas

So, much like our regular old chicken fajitas recipe, our mushroom version is also essentially a sheet pan recipe. In other words, this magical dinner recipe is vegetarian AND a one-pan meal! YAY. Here’s how to make these delicious mushroom fajitas:

  1. Slice the portobello mushrooms and toss them in taco seasoning, olive oil and lime juice.
  2. Grab your sheet pan, and load it up with the all of the vegan fajita filling goodies—sliced bell peppers, onions and the marinated portobello slices. Roast for about 20 minutes.
  3. Warm the tortillas while your mushrooms and veggies roast. You can do this in the oven, but be mindful—at 450°F, they’ll warm quickly! We usually prefer to warm them in a skillet on the stovetop.
  4. While the veggies roast, you might also want to whip up that guacamole.
  5. Serve! Fill those warm flour tortillas with the roasted mushrooms, peppers and onions, and top generously with creamy, homemade guacamole.
vegan Portobello Mushroom Fajitas on a sheet pan with tortillas
vegan Portobello Mushroom Fajitas on a sheet pan in tortillas on a plate

Tools You’ll Need:

More Easy Vegetarian Recipes You’ll Love:

Whether you’re looking for a quick meatless Monday recipe, or you’re devoted to a plant-based diet, these five vegan recipes are sure to be new favorites:

vegan Portobello Mushroom Fajitas on a sheet pan in tortillas on a plate

Healthy & Delicious—Our Favorite Combo.

Satisfying and delicious, these vegan fajitas are a sure-fire hit. If you try them, we want to hear how you liked them! Snap a photo of your portobello fajitas and tag us on Instagram using @themodernproper and #themodernproper. Happy eating!

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Portobello Mushroom Fajitas

  • Serves: 4
  • Prep Time:  10 min
  • Cook Time:  20 min
  • Calories: 160


  • ¼ cup homemade taco seasoning (or 2 tbsp store bought)
  • 2 tbsp olive oil
  • 1 tablespoon lime juice (from 1 lime)
  • 1 ½ lbs portobello mushrooms, cut into thick ¾-inch slices
  • 1 red onion, sliced
  • 1 red bell pepper, sliced
  • 1 orange bell pepper, sliced
  • 1 yellow bell pepper, sliced
  • small flour tortillas
  • guacamole
  • cilantro


  1. Preheat oven to 450°F.
  2. In a large bowl make a marinade using the taco seasoning, olive oil and lime juice.
  3. Toss the portobello mushrooms in the marinade until evenly coated.
  4. Spread ingredients across an oiled baking pan and bake for 20 minutes. If you want to add some char to the mushrooms and veggies, broil for another 3 minutes.
  5. Serve with warm tortillas, salsa, guacamole, avocado, and fresh cilantro.

Nutrition Info

  • Per Serving
  • Amount
  • Calories160
  • Protein8 g
  • Carbohydrates23 g
  • Total Fat8 g
  • Dietary Fiber5 g
  • Cholesterol0 mg
  • sodium241 mg
  • Total Sugars7 g

Portobello Mushroom Fajitas

Questions & Reviews

Join the discussion below.

  • Tamara

    Only marinade the mushrooms? Don’t add the peppers?

    We usually just do the mushrooms, yes.

  • Jess

    If I didn’t read the blog and only read the recipe I would have completely missed the “marinade for one hours”. I don’t see it in the actual recipe, could be missing it. Still good with less marinade time ?

    Thanks for bringing this to our attention Jess! We will update the instructions. It will still be good if you don't marinade for an hour.

  • Gordon

    These are not GF as advertised since they call for flour tortillas

    Hi Gordon, you can just swap for corn tortillas to make it gluten free. Hope you enjoy!

  • Su

    What can I serve this with in order to get more protein in the meal? Preferably, a vegetarian source of protein.

    We really love soy curls! They'd be delicious in this. Or you could add some veggie sausage!

  • Sophia

    Absolutely amazing, the flavours were perfect!

    Thanks Sophia, we are so glad you loved it!

  • Karla

    My husband and I are meat lovers. However, we are trying to incorporate more plant based options in our diet. We both loved this. Thank you!

    Thanks Karla, we are so happy you loved it! Our Kung Pao mushrooms are a super delicious plant based option, you should check it out!

  • Douglas

    This is remarkably good! I marinaded the mushrooms for an hour, and I drizzled a little olive oil over the peppers and onion before baking. It's a lot while raw, but it reduces once cooked. I cooked what didn't fit on the cookie sheet in a cast iron stove-top, which may have been even better. This is a winner. I'll do it again!

    Thanks Douglas, we are so happy you enjoyed it!

  • Mary

    Excellent. Had all the ingredients and some portabellos I didn't have a real plan for. Prefect dinner
    Quick and tasty. Thanks?

    Thanks Mary Ann, we are so glad you loved it!

  • Briana

    I tried this recipe! It was absolutely delicious! *chef’s kiss* My favorite! Thank you so much for sharing this meal, especially because it’s meatless!

    Thanks Briana, we are so glad you loved it!