This recipe for portobello mushroom fajitas is a delicious, meatless alternative to the classic fajita. With its spicy Tex-Mex flavor and a mix of colorful peppers, onions, and meaty portobello mushrooms, it is a quick and easy dish that will disappear from your table in no time.
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❤️ Why you’ll love it
I love how this recipe simplifies the process of making fajitas. The oven method for preparing the filling is not only easy but also ensures that all the ingredients are cooked to perfection.
The combination of bell peppers, onions, and portobello mushrooms seasoned with a homemade fajitas spice mix is so flavorful that you will not miss the meat.
What is best is that the variety of toppings, including guacamole, salsa, black beans, and vegan sour cream, adds an extra layer of deliciousness, making this a full-course meal. It is satisfying, delicious, and everything you could ever want in a home-cooked meal.
🧾 Key ingredients
These portobello fajitas require only pantry staples for an irresistible flavor. You would be surprised how simple ingredients can result in such great taste.
Portobello mushrooms are the star of this dish, providing a hearty, meaty texture that is satisfying and filling. These large mushrooms are perfect for soaking up the flavors of the fajita spice mix.
Red onion and bell peppers add a burst of color and a sweet, tangy flavor to the fajitas. They are sautéed until soft and caramelized, enhancing their natural sweetness.
The homemade fajitas spice mix is a blend of hot chili powder, sweet smoked paprika, ground cumin seeds, garlic powder, and oregano. This homemade mix infuses the vegetables with a smoky, spicy flavor that is characteristic of traditional fajitas.
Tortillas serve as the base for these fajitas. You can use store-bought tortillas or try my homemade flourless tortillas for a healthier, gluten-free option.
🛒 You can find detailed measurements for all ingredients in the printable version of the recipe card at the bottom of this post.
For this delicious portobello mushroom fajitas recipe, the most crucial piece of equipment you will need is a sheet pan. This versatile kitchen tool allows you to roast all your veggies and mushrooms in one go, ensuring they are evenly cooked and full of flavor.
Making the portobello mushroom fajitas
Preheat your oven to 430°F (220°C). While waiting, peel and slice the onion into ¼-inch (4-5 mm) wide pieces.
Wash and slice the bell peppers into ¼-inch (4-5 mm) wide pieces.
Rinse the portobello mushrooms if they are dirty. If they are clean, just gently wipe them with a damp towel. Cut off the stems and slice the mushrooms into ¼-inch (4-5 mm) wide pieces.
Place a sheet of parchment paper on a sheet pan. Arrange the sliced onion, bell peppers, and mushrooms on the pan, preferably in a single layer.
Drizzle the vegetables with olive oil. Season them with half of the fajitas spice mix, salt, and pepper. Use tongs to mix the vegetables until they are evenly coated with the oil and seasonings.
Place the sheet pan in the preheated oven. After 10 minutes, remove the pan from the oven.
Turn the vegetables with tongs and sprinkle them with the remaining half of the spice mix. Return the pan to the oven and roast the vegetables for another 10 minutes. The vegetables should be served sizzling hot.
To assemble your fajitas, take a soft tortilla. Most store-bought brands are vegan. Place a few strips of mushroom, bell pepper, and onion in the middle of the tortilla. Top the vegetables with guacamole, salsa, black beans, and vegan sour cream. Enjoy your delicious vegan portobello mushroom fajitas.
💡 Expert tip
To ensure your fajitas are packed with flavor, do not skip the step of seasoning your vegetables twice. First, season them before roasting, then again halfway through. This double seasoning ensures that every bite is bursting with the delicious fajita spice mix.
Bring in some different textures with tofu. If you want to add more protein to your sheet pan fajitas, why not include some crispy tofu? It will provide a unique texture and absorb the flavors of the fajitas spice mix. Remember to press the tofu before cooking to remove excess water and achieve a firmer texture.
If you like your food with a bit of heat, consider adding some jalapeno peppers. These peppers will give your portobello mushroom fajitas a spicy kick without overpowering the other flavors. You can adjust the amount of jalapeno peppers according to your heat tolerance.
Experiment with different types of mushrooms. The beauty of this recipe is its versatility. You can try using different types of mushrooms like shiitake, oyster, or cremini. Each type of mushroom will bring a unique flavor and texture to this recipe.
🥣 Serving ideas
Portobello mushroom fajitas is a versatile dish that can be enjoyed in many ways. You can add so many other delicious ingredients to take them to the next level.
Serve it in some soft tortillas along with your favorite chunky salsa, some homemade fajita veggies, guacamole, black beans, sour cream, and of course lime and cilantro for a classic take.
You can also experiment with different salsa flavors. Consider pairing them with a hot sauce or a fresh salsa. You can try a savory-sweet pineapple mango salsa recipe from Caramel and Cashews or the tomato corn salsa fresca in my burrito bowl recipe.
These fajitas pair well with a variety of vegetable sides. Try serving them with roasted bell peppers, sautéed onions, or julienned carrots for a refreshing and hearty meal.
❄️ Storing tips
Storing and reheating portobello mushroom fajitas is easy, and it does not compromise the flavor.
To store the leftovers, allow them to cool completely. Once cooled, transfer them to an airtight container and place it in the refrigerator. The fajitas should stay fresh for about 3-4 days.
Unfortunately, freezing is not recommended for this recipe. The texture of the mushrooms and the vegetables can become mushy and unappetizing when thawed and reheated. Therefore, it is best to enjoy them fresh or refrigerated.
When you are ready to enjoy them again, you can reheat them. Place them in a pan over medium heat, stirring occasionally until they are heated through. Alternatively, you can reheat them in the microwave, but remember to stir them every 30 seconds to ensure even reheating.
Yes, you can. This recipe is quite flexible. You can add other vegetables like zucchini, carrots, or even spinach. Just make sure to slice them thinly and adjust the cooking time as needed.
The fajitas spice mix adds a burst of flavor to the vegetables. It is a blend of hot chili powder, sweet smoked paprika powder, ground cumin seeds, garlic powder, and oregano.
Absolutely! You can make a larger batch of the spice mix and store it in an airtight container. It will stay fresh for up to 6 months.
Start by placing a couple of mushroom strips, bell pepper, and onion slices in the middle of a tortilla. Then, add some guacamole, salsa, black beans, and sour cream on top. Fold the tortilla and enjoy.
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Sheet Pan Portobello Fajitas
Homemade fajitas spice mix
Making the filling
- The EASIEST way to make veggies for fajitas is in a sheet pan.
- Peel and slice onion ¼-inch (4-5 mm) wide.
- Wash and slice bell peppers also ¼-inch (4-5 mm) wide.
- Rinse portobello mushrooms if they are dirty. Otherwise, just gently clean them with a damp towel. Cut the stems and slice them ¼-inch (4-5 mm) wide.
- Place parchment paper in a sheet pan. Place all veggie and mushroom strips on it, preferably in one layer.
- Sprinkle them with olive oil and season them with half of the fajitas spice mix, salt, and pepper. Mix them with tongs.
- Roast them in a preheated oven of 430 Fahrenheit (220 degrees Celsius).
- After 10 minutes, take the sheet pan out, turn the veggies with tongs and sprinkle them with the other half of the spice mix. Roast them for 10 more minutes. Fajitas veggies are best served sizzling hot.
Assemble your fajitas
- Take a soft tortilla. (Most of the store-bought brands are vegan)
- Place a couple of mushroom strips, bell pepper, and onion slices in the middle of the tortilla.
- Then scoop some guacamole, salsa, black beans, and sour cream on top. Enjoy!
- Use a sheet pan with parchment paper. We recommend using a sheet pan because it has sides. If you use a baking sheet, the juices from the veggies during roasting might not flow off of it.
- Cut veggies into equal strips. This is to make sure the vegetables are ready at the same time.
- Place veggies in batches on the sheet pan. They will be easier to mix, match, and serve if they are grouped.
- Hot and sweet together? – If you prepare the veggies for kids or people who don’t like spicy food, roast hot chili peppers separate from all other veggies. If you roast hot chili peppers and bell peppers together, the juices of the hot chili peppers may make the sweet bell peppers also spicy and hot.
- Other ways to make fajitas veggies. After preparing and cutting your veggies, you can use other ways to get them ready like 1) Sautee them in a cast-iron skillet or grill pan or griddle or 2) Grill them in aluminum foil drip pans on your BBQ.