Portobello mushrooms turn into meaty, savory vegan fajitas with one sheet pan and 30 minutes. This plant based weeknight dinner is a winner!
How to make homemade vegan fajita seasoning
These 30 minute vegetarian fajitas are flavor-packed. And all that flavor comes from our homemade fajita spice blend. It’s warming, a bit sweet, with just the right amount of heat. Plus, if you’re looking to make this dinner even faster, you can make the spice blend ahead of time. Just whip it up and store it in an airtight container.
You could even make a big batch of our fajita seasoning. Then, you’ll have some on hand to flavor any kind of vegetable or protein. It’s very versatile and I’m sure you’ll find some creative ways to use it!
If you’ve got meat lovers in the family, the fajita spice could flavor chicken, beef or pork. Or, sprinkle it over all kinds of vegetables. Then roast them up or make a fajita spiced stir fry for dinner. This seasoning would also be delicous on crumbled tofu or beans for a plant-based high-protein dinner.
Here’s how we build our fajita seasoning:
- Coconut sugar. This natural sweetener adds a bit of sweetness to our fajitas. It’s also a nice caramel color, which adds browning to our fajita vegetables. Coconut sugar has a lower glycemic index than regular sugar, so it doesn’t cause big blood sugar spikes. And, it has a very mild coconut flavor that melts right into our meaty portobello mushrooms.
- Chili powder. A classic Mexican spice, chili powder packs just a hint of heat. It’s fairly mild, so we add a whole tablespoon and a half to our seasoning blend.
- Cumin. Cumin is a foundational Mexican spice. It’s warming and nutty.
- Garlic powder. We rely on garlic powder for most dry spice blends. A little goes a long way though! It packs a lot of garlicky flavor, and unlike fresh garlic, it lasts a long time in your pantry.
- Paprika. One of my personal favorite spices, paprika is the secret to smoky flavor without a grill. Or even going outside. You can pack smokiness into your meals all year long with a stocked supply of smoked paprika.
- Dried oregano. If you can, go for Mexican oregano for these fajitas. It’s less finely ground, which adds texture to the spice blend. It’s also more floral tasting.
- Cayenne. This is where most the heat in our fajitas come from. Use only as much as you like. If you’re very sensitive to spice, you could also leave the cayenne out. But I recommend at least a quarter teaspoon to bring some spice to your plate.
After mixing all of these fragrant Mexican spices together, you’ve got a flavor-packed homemade spice blend to use whenever you want! Now, just sprinkle it over your vegetables and you’re 20 minutes from these vegan mushroom fajitas.
30 Minutes + 1 Sheet Pan = Dinner
While mushrooms steal the show of this satisfying plant-based dinner, we had to toss some more vegetables in for color and, of course, nutrition. We like a fajita that’s hard to close, there’s so much delicious vegetable filling packed inside.
Potatoes add heartiness and make this sheet pan dinner super filling. You can use your favorite kind of potato. We used white potatoes, but purple would make a beautiful accent. Sweet potatoes would work, too! The key is to cut the taters into thin wedges of the same size. That way, they’ll cook at the same time as the mushrooms and other veggies.
Purple onion complements our portobellos in these fajitas. They provide a foundational sweet flavor. If you ask me, no meal is complete without melty onions! And they cook up so nicely in the oven. You’ll get the beginning of caramelization in just a few minutes. (That’s thanks to the coconut sugar in the fajita seasoning.)
Yellow and green peppers bring festive color to these fajitas. And what’s better than peppers and onions? Of course, you can use whichever pepper color you like best. Red or orange would add even more brightness.
When you’re making these sheet pan mushroom fajitas, slice everything in similar sizes. Also, don’t be afraid to break out a second sheet pan.Whenever you roast veggies, you want to give them plenty of space. If they’re touching or too close together, you’ll end up steaming the veggies rather than roasting them.
Remember: space makes things crispy!
Assembling Vegan Portobello Fajitas
Now comes the fun part. It’s time to top and assemble your vegan portobello fajitas! Sliced avocado (or guacamole) is a no-brainer. Fresh cilantro and lime slices brighten everything up.
Lastly, if you have a few extra minutes, you could mix up a batch of quick-pickled onions. These are the kind of pickles that truly live up to their name. In just a few minutes, you’ll have delicious pickled onions without any of the harsh bite from raw red onion!
We have a full guide on how to make quick pickles with nearly any vegetable, but red onions are the perfect place to start. All you do is heat some water and vinegar. This combo, poured over sliced red onion, mellows everything out. The result is soft and silky pickled onion that packs brightness without bite!
Finally, before digging into these mushroom fajitas, warm your tortillas. You can pop them into the oven directly on the racks. They’ll warm up in just 2 minutes.
If you’re gluten-free, we like Siete grain-free tortillas. Store them in the freezer to keep them fresh. In general, we opt for corn tortillas. They’re flexible and tastier than flour tortillas, in my opinion.
For more topping ideas, you could dollop these vegan portobello fajitas with vegan sour cream. Follow Your Heart makes a good store-bought option. Or, you could make your own homemade dairy free sour cream with Cookie and Kate’s recipe. And if you like more spice, add a dash of your favorite hot sauce.
More Vegan Mexican Dinners
If you’re like me, these vegan portobello fajitas will send you on a serious Mexican kick. Well, you’ve come to the right place. We’re always working on zesty and spicy new vegan recipes that highlight Mexican ingredients.
Here are some of our favorites:
- Vegan Burrito Bowls. These work for breakfast, lunch or dinner. They also make excellent vegan meal prep.
- Vegan Taco Lettuce Wraps. Another quick and easy weeknight dinner. This one’s also fun to eat and make. You can serve the lettuce wraps family style and let everyone pile on as much taco spiced mushroom lentil filling as they like.
- Taco Stuffed Avocados. In case you can’t tell, we like stuffing vegetables with taco-spiced filling. This filling is similar to the lettuce wraps, but gets an upgrade to an avocado boat. Talk about a satisfying vegetarian dinner recipe.
- Loaded Vegan Nachos. Now that football season is in full swing, it’s time to make these game day nachos every Sunday.
- Spicy Breakfast Potato Tacos. Why not start your day with tacos? These vegan and gluten free tacos are filling, spicy and savory. We’re all about potato-filled, savory breakfasts over here.
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Portobello mushrooms turn into meaty, savory vegan fajitas with one sheet pan and 30 minutes.
- 1 tbsp coconut sugar
- 1½ tbsp chile powder
- 1 tbsp cumin
- 1½ tsp garlic powder
- 1¼ tsp paprika
- 1 tsp dried oregano
- ¼–½ tsp cayenne, depending on how spicy you want it
- 1¾ –2 tsp kosher salt
- ½ tsp black pepper
- 2 medium or 3 small portobello mushroom caps, sliced
- 2 cups potato, thinly sliced
- 1 large purple onion, thinly sliced
- 1 large red pepper, sliced
- 1 large green pepper, sliced
- ½ cup olive oil
- 1½ tbsp lime juice
- ⅓ cup freshly chopped cilantro, plus more for topping.
- 4 gluten free tortillas
- 1 tomato, sliced thinly, for topping
- Pickled red onion, for topping
- 1 avocado, sliced thinly, for topping
- Preheat oven to 400. Line a baking sheet with parchment paper. In a small bowl, combine the coconut sugar, chile powder, cumin, garlic powder, paprika, oregano, cayenne, salt and pepper.
- Add the mushrooms to one bowl and the potato, onion and peppers to a separate bowl. Whisk the olive oil and lime juice together. Add 2 tbsp of the spice blend, 2 tbsp of the oil mixture, and 1 tbsp chopped cilantro to the mushrooms and toss very gently to avoid breaking up the mushrooms. Add the rest of the spice blend, chopped cilantro, and olive oil mixture to the rest of the vegetables and toss well to coat evenly.
- Spread the veggies out on the prepared baking sheet and roast for 25 minutes, stirring halfway. You may need two baking sheets if the veggies don’t fit on one in a single layer.
- Before serving, warm the tortillas directly on the oven racks for 2 minutes.
- Serve the fajita veggies on warmed tortillas topped with sliced tomatoes, pickled purple onions, avocado, and fresh cilantro.
You could also add tofu to the sheet pan for protein or serve with black or pinto beans. For the meat lover in your family, try adding thinly sliced beef or sliced chicken.
Keywords: sheet pan dinner, mushroom fajitas, portobellos, mushroom fajita sheet pan dinner