This flavor-packed vegan fajitas recipe is made with Portobello mushrooms and other tasty veggies. It's marinated for maximum flavor and baked on a sheet pan for super easy cooking.
Serve this mushroom filling in tortillas with all your favorite toppings for a crowd-pleasing meal! This recipe can be made gluten and soy free if needed.
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Veggie Fajitas Recipe Ingredients
The ingredients for this recipe are simple but work together to create mouth-watering fajitas.
- Portobello mushrooms: Mushrooms are the star of this recipe. Portobellos are meaty, earthy mushrooms that many vegans use as a steak replacement. You can use other types of mushrooms, but Portobellos are best for their texture and size.
- Bell peppers: Use any colored bell peppers you like for a tasty fajita veggie mix.
- Onion and garlic: Fajitas are typically made with lots of onion as a main vegetable and it’s a great way to add flavor. Garlic is also a must for me as I include this tasty ingredient in almost all my recipes.
- Vegetable oil: Some oil helps the veggies cook nicely, not stick to the pan and roast to slightly blackened perfection. Use any neutral-tasting vegetable oil you like; I typically use avocado oil for this recipe.
- Soy sauce: While this isn’t a typical fajita ingredient, the saltiness and umami flavor of soy sauce creates a rich-tasting dish. This is especially helpful when trying to make a vegan meal taste as delicious as something that would typically include meat. Use tamari for a gluten-free option or coconut aminos for a gluten and soy free option.
- Lime juice: Fresh lime juice elevates all the flavors in these fajitas. The acidity and bright flavor heightens every other ingredient. You could use lemon juice, but lime has the best flavor for making veggie fajitas.
- Agave syrup: Some sweetness helps balance flavors and agave syrup has the perfect flavor to pair with fajitas. You may want to use maple syrup instead.
- Tomato paste: Concentrated tomato flavor is a great addition to fajitas. The flavors of tomato paste become more complex and caramelized as the fajita veggies roast.
- Nutritional yeast: This tasty ingredient adds a nice depth of flavor to the recipe. Nutritional yeast is slightly nutty and cheesy in taste, adding an extra layer of umami flavor. Nutritional yeast is NOT the same as traditional yeast and these ingredients cannot be substituted for one another.
- Taco seasoning: To keep things simple, I use homemade taco seasoning for the spice blend in this recipe. Use any taco or fajita seasoning mix that you like (homemade or store-bought).
- Cilantro: While technically optional, chopped, fresh cilantro helps add lots of flavor to these fajitas. Since the veggies have a bold, spicy flavor, cilantro helps brighten that. A drizzle of extra lime juice could also work if you aren’t a fan of cilantro.
How to Make Vegan Sheet Pan Fajitas
This recipe is extremely easy to make. Almost all the time needed is for the veggies to marinate then bake. With very little effort you can enjoy delicious, homemade sheet pan fajitas!
Step 1: Slice Vegetables
Gently wash, then slice some mushrooms and bell peppers.
You’ll also need to peel and slice the onion, then peel and mince garlic.
I don’t recommend using a garlic press for this recipe. Minced garlic creates slightly larger pieces which are less likely to burn in a hot oven compared to the fine texture of pressed garlic.
Step 2: Marinate Veggies
Add your prepared vegetables to a large container with a lid, then add all the remaining ingredients except for cilantro.
Refrigerate the container, with its lid on, letting the vegetables marinate for at least 2 hours. Overnight is best if you have the time and forethought!
If possible, toss the veggies around every few hours. This keeps all the marinade flavors evenly tossed onto your vegetables.
Step 3: Bake and Serve
When ready to bake, preheat your oven to 425 °F.
Place the marinated vegetables onto a baking tray that has edges. While I typically use a silicone baking mat (or parchment paper) for easy clean-up, that does not work for this recipe. Place the veggies directly on your sheet pan.
Bake for 25-35 minutes, until the vegetables are cooked and start to crisp on top. There shouldn’t be any liquid left on the baking tray (there will be a lot of steam/ water released from the vegetables as they cook and they will shrink).
If you want a slightly blackened fajita mix, place your veggies under a broiler, set to high heat, for 1-2 minutes. Keep a very close eye on the vegetables and never leave anything unattended when using a broiler (food can burn within seconds).
Once out of the oven, toss freshly chopped cilantro over your fajita vegetables. You can also add a fresh squeeze of lime juice.
Serve with tortillas and all your favorite fajita toppings.
How to Create a Balanced Vegan Meal
I believe it’s fine to occasionally consume a lower protein meal like these vegetable fajitas. This works if you regularly eat higher protein foods (like beans, lentils, legumes and soy).
Vegans can run into issues when regularly using mushrooms or other vegetables (like cauliflower, eggplant, jackfruit, potatoes, hearts of palm and artichoke) as meat substitutes without the addition of higher protein foods.
If you want to add protein to this meal, toss in some crumbled tofu or tempeh, cooked TVP or black beans.
This meal is loaded with veggies and there’s healthy fats from vegetable oil. If you want an extra-satisfying meal that’ll keep you feeling fuller for longer, try adding avocado or guacamole.
If serving these fajitas in a tortilla wrap, you’ll get in some energizing carbohydrates; otherwise, this is a fairly low carb recipe (which can work for some people, but not others).
Vegan Fajita Recipe Variations
There’s plenty of ways to prepare vegan fajitas, and even more fun ways to serve them. You can make fajitas in tortilla wraps or a fajita bowl.
Get creative with your toppings too! Some fun ideas to try are:
- Black bean and corn salsa
- Guacamole or sliced avocado
- Vegan cheese shreds
- Vegan sour cream (homemade or store-bought)
- Fresh or pickled jalapeno peppers
- Chopped tomato
- Fresh lime juice
- Shredded lettuce
If you’d rather try a different type of vegan fajita altogether, try out my recipe for vegan jackfruit fajitas!
How to Refrigerate and Reheat these Fajitas
Cool leftover fajita vegetables to room temperature before transferring to an airtight container. You can refrigerate them for up to 5 days.
To reheat, microwave or use a pan on the stove over medium heat until warmed through.
You could also reheat in the oven but it’s not necessary. To use this option, reheat on a baking tray with the oven at 350 °F until the vegetables are warmed through.
Store any leftover fajita toppings and wraps separately.
If you make this recipe, please rate and comment below to help others benefit from your experience!
Vegan Fajitas with Portobello Mushrooms
- Baking tray (with edges)
- Large container with lid
- Measuring cups
- Measuring spoons
- 4 large portobello mushrooms (375 grams)
- 2 cups onion (about 1 large, 210 grams)
- 3 cups bell pepper (about 3 medium, 475 grams)
- 4 cloves garlic
- 3 tablespoons vegetable oil (45 milliliters)
- 3 tablespoons soy sauce (or tamari, 45 milliliters)
- 2 tablespoons lime juice (30 milliliters)
- 2 tablespoons agave syrup (30 milliliters)
- 2 tablespoons tomato paste (30 milliliters)
- 2 tablespoons nutritional yeast
- 1 ½ tablespoons taco seasoning
- ½ cup cilantro , chopped (optional, 10 grams)
- tortilla wraps
- extra toppings
Step 1: Slice Vegetables
- Chop your mushrooms and other vegetables into a container with seasonings.4 large portobello mushrooms, 2 cups onion, 3 cups bell pepper, 4 cloves garlic, 3 tablespoons vegetable oil, 3 tablespoons soy sauce, 2 tablespoons lime juice, 2 tablespoons agave syrup, 2 tablespoons tomato paste, 2 tablespoons nutritional yeast, 1 ½ tablespoons taco seasoning
- Secure a tight-fitting lid to the container.
Step 2: Marinate Veggies
- Refrigerate and let the vegetables marinate for at least 2 hours (overnight is best).
Step 3: Bake and Serve
- When the vegetables are marinated, preheat your oven to 425 °F.
- Place the vegetables onto a baking tray in an even layer.
- Bake 25-35 minutes, until the vegetables are cooked and starting to crisp on top.
- For more of a blackened option, place the vegetables under a broiler on high for 1-2 minutes (keeping a very close eye on it so it doesn’t burn).
- When out of the oven, sprinkle your vegetables with chopped cilantro.½ cup cilantro
- Serve in tortillas with all your favorite fajita toppings.tortilla wraps, extra toppings
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About Nicole Stevens
Nicole is a vegan Registered Dietitian (RD) and founder of Lettuce Veg Out.
She helps people thrive on a vegan diet with balanced recipes and easy-to-understand nutrition science.