Mushroom Fajitas with Cashew Queso Blanco

By Alexandra Caspero on January 9, 2023

Restaurant worthy fajitas made with portobello mushrooms, peppers and onions!

Serves 4

The best mushroom fajitas! Incredibly flavorful portobello fajitas with peppers and onions. Vegan and easily gluten-free– these portobello mushroom fajitas are a must make!

vegetarian fajitas with tortillas and salsa

Coming into the new year with a sizzling new recipe– mushroom fajitas! If you love my simple oven roasted fajitas or veggie fajita enchiladas then you’ll love this mushroom-packed version. With brightly colored bell peppers, portobello mushrooms and a simple cashew queso blanco sauce.

I think I’ve finally cracked the code on how to get perfect fajitas at home– and that is using a griddle to cook them! Once I had this a-ha moment, it felt so silly because of course that’s the best way! Using a griddle increases surface area which means you get maximum caramelization of the fajita vegetables. This translates to golden brown on the outside and tender on the inside hunks of vegetables.

You have to try these! They are so incredibly delicious, especially with my simple cheesy cashew sauce.

platter of mushroom fajitas with cashew cheese

Why we love these

Simple ingredient list. This one comes together with just a handful of fresh vegetables, tortillas and pantry spices!
Endless topping combinations. Isn’t that the best part of fajitas! You can top these with your favorite salsa (I’m partial to my canning salsa that I always have stocked) or try my simple cashew cheese recipe below!
Healthy and Plant-Based. These fajitas are loaded with a few servings of vegetables and customizable to various dietary patterns. For my gluten-free friends, simply sub in corn tortillas!

Portobello Fajita Ingredients

Make sure to scroll down to the recipe card for the full set of ingredients and directions. These weeknight fajitas come together quickly, thanks to a handful of ingredients:

Fresh Produce: Portobello mushrooms, garlic, onions and bell peppers
Seasonings: Pantry staples like chili powder, cumin, oregano and paprika
Tortillas: Flour tortillas are my go-to choice here, but corn tortillas are great to keep this recipe gluten-free
Toppings: Red Salsa, Jalapeno Salsa and Guacamole, for serving along with my recipe for cashew cheese, below! Fresh sliced avocados are also great in this mushroom fajita recipe

Ingredient Substitutions

I highly recommend portobello mushrooms in this recipe over other mushrooms as they are meatier and can stand up better to the peppers and onions. If you can only find (or have!) button mushrooms, then you won’t need to cook them as long in the oven. The oven step helps to dry the mushrooms slightly so they are browned on the outside when cooking in the griddle and not watery.

For additional protein and fiber, I sometimes serve these with a generous scoop of black beans on top. Pinto beans also work, as does a smear of refried beans on the bottom!

Any toppings work on these portobello fajitas– I prefer my red blender salsa, jalapeño salsa and cashew cheese (the perfect pairing of smoky, spicy and cooling!) but you can also use store bought shredded cheese or sour cream if desired.

How to Make Mushroom Fajitas

Here’s a quick overview of the process with photos. Full directions in the recipe card at the bottom!

Bake the mushrooms
This step helps to release some of the water that’s naturally in the mushrooms. If you’re in a time-crunch, you can skip it– but this process will make for the best portobello fajitas! Season with garlic, seasonings and olive oil, then roast for 15-minutes.
Sauté the onions and peppers
A large griddle is best for this as it provides a large surface area to allow all of the peppers and onions to brown nicely. If you don’t have a griddle, then a large skillet pan will work instead. Add in the cooked mushrooms and a squeeze of fresh lime juice!
Make the Queso Blanco
If you want to add in the cheesy cashew sauce, place all of the ingredients into a blender or food processor and process until well-combined and smooth.
Assemble!
Lightly griddle the tortillas either over a gas flame or an ungreased skillet, then top with fajitas and whatever toppings you are using.

Tips for Success

After making different versions of fajitas over the years, the key is not crowding the peppers and onions in the pan! This makes them steam, instead of brown. Therefore I highly recommend a large griddle pan, like the cast-iron one I’m using, or a similar large pan.

Precooking the mushrooms in the oven also allows for a heartier mushroom! This prevents any sogginess that can sometimes happen when cooking mushrooms in a pan. I don’t recommend skipping this, but if you are short on time, then I recommend cooking the mushrooms first in the skillet until almost browned, then removing and cooking the peppers and onions. When almost finished, add the mushrooms back in.

Make sure to clean your mushrooms well before cooking; I do remove the stems but keep the gills on! That’s a personal preference and up to you.

Lastly, this recipe is easily doubled (or tripled) but may need to be done in batches so the vegetables can brown.

Frequently Asked Questions

What vegetables should I put in fajitas?

Peppers and onions are a classic ingredient, but this mushroom fajitas recipe is customizable to whatever vegetables you like! Zucchini and squash are also great fajita vegetables because the break down and easily brown on the outside.

What toppings do you put on fajitas?

Your favorite taco toppings will also work on fajitas! I love a mix of smoky, spicy and cooling which is why I prefer to serve these alongside my rojo salsa, my jalapeno salsa and my cashew cheese.

What is traditionally served with fajitas?

When making these for my family, I typically serve them with warmed black beans and cilantro lime rice!

Mushroom Fajitas with Cashew Queso Blanco

Author: Alex Caspero
Prep Time: 15 minutes
Cook Time: 20 minutes
Total Time: 35 minutes
Yield: 4 servings 1x
Category: dinner, recipe, main, fajitas
Method: Stove Top
Cuisine: American, Tex-Mex, Mexican Inspired
Diet: Vegan

Description

The best mushroom fajitas! Incredibly flavorful portobello fajitas with peppers and onions. Vegan and easily gluten-free– these portobello mushroom fajitas are a must make!

Print Recipe

Author: Alex Caspero
Prep Time: 15 minutes
Cook Time: 20 minutes
Total Time: 35 minutes
Yield: 4 servings 1x
Category: dinner, recipe, main, fajitas
Method: Stove Top
Cuisine: American, Tex-Mex, Mexican Inspired
Diet: Vegan

Author: Alex Caspero
Prep Time: 15 minutes
Cook Time: 20 minutes
Total Time: 35 minutes
Yield: 4 servings 1x
Category: dinner, recipe, main, fajitas
Method: Stove Top
Cuisine: American, Tex-Mex, Mexican Inspired
Diet: Vegan

Scale

Ingredients

3 portobello mushrooms, stems removed and sliced 1/2-inch thick
1 teaspoon chili powder
1 teaspoon ground cumin
2 tablespoons oil
1/2 teaspoon salt
2 minced garlic cloves
2 medium onions, thinly sliced
2 poblano peppers, sliced
2 red bell peppers, sliced
2 teaspoons dried oregano
1/4 teaspoon smoked paprika
2 teaspoons fresh lime juice
Tortillas, for serving
Red Salsa, Jalapeno Salsa and Guacamole, for serving

Cashew Queso Blanco

1 cup cashews, soaked for 15 minutes in boiling water (this makes it easier to blend)
2 tablespoons fresh lemon juice
1/4 cup water
1 heaping tablespoon nutritional yeast
1/2 teaspoon salt
1 (4 ounce) can roasted green chilis

Cook Mode Prevent your screen from going dark

Instructions

Preheat oven to 350 degrees F. Toss mushrooms with 1/2 teaspoon chili powder, 1/2 teaspoon cumin, 1 tablespoon oil, garlic cloves and 1/4 teaspoon salt. Spread in a single layer on a greased baking sheet (or silpat-lined or parchment-paper lined) Bake for 15 minutes, then remove
Heat a large skillet (or, for best results, a griddle or cast-iron griddle) over medium-high heat. Add the oil to the griddle along with the onions. Cook, stirring often, until onions are softened, about 10 minutes.
Add the sliced peppers, remaining 1/2 teaspoon chili powder, 1/2 teaspoon cumin, 1/4 teaspoon salt, oregano, and paprika. Cook, stirring often, for 10 minutes until peppers are cooked down and lightly charred on the edges. Stir in the cooked mushrooms and lime juice. Season to taste, adding more salt, as desired.
For the Cashew Queso Blanco: Place the drained cashews, lemon juice, water, nutritional yeast, salt and canned chili peppers until very creamy and smooth. Season to taste, adding more salt and nutritional yeast, as desired.
Warm tortillas and fill with the fajita filling and toppings of choice: Cashew Queso Blanco, Salsa and Guacamole.

Notes

I highly recommend a griddle or cast-iron griddle for this recipe. Testing it in both a griddle and a skillet, the griddle produced the classic char on the ends of the peppers and onions that a skillet didn’t.
The lime juice addition is optional, but I find that it provides a nice balance to the smoky fajitas.
For a gluten-free recipe, use corn tortillas.

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Meet Alex Caspero

Alex Caspero is a Registered Dietitian, New York Times Bestselling Plant-Based Chef and mom of two. She aims to cut through the nutrition noise by providing real-life, nourishing tips for body and mind. Learn more about Alex.