Mushroom Fajitas with Spiced Black Beans
These Mushroom Fajitas are built around hearty roasted portobello, colorful bell peppers, and a side of boldly Spiced Black Beans. A satisfying plant-based dinner that comes together in about 45 minutes and works for Plant-Based Whole30.
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Whether you’re looking for an easy weeknight meal or a plant-based fiesta, these Mushroom Fajitas are the perfect solution to satisfy your craving. Hearty portobello mushrooms hold up beautifully to high heat, developing a meaty, slightly charred texture that makes them great for these vegetarian fajitas. Paired with colorful bell peppers, red onion, and a side of boldly spiced black beans, this is a plant-based dinner that doesn’t feel like a compromise.
As a recipe developer focused on plant-based and pescatarian cooking, I’ve leaned on portobello mushrooms as a reliable centerpiece ingredient for years. They absorb marinades well, roast evenly, and bring a depth of flavor that works naturally in dishes like fajitas where seasoning and texture do the heavy lifting. This recipe is also Plant-Based Whole30 compatible, making it a go-to when I need something that fits stricter eating without sacrificing flavor.
My Taco and Fajita Spice Blend is what seasons the mushrooms and vegetables here. I keep it in my pantry at all times, and it makes this recipe significantly faster to pull together on a weeknight.
What You Need for Mushroom Fajitas
This recipe has two components, making it a complete meal. The roasted mushroom fajitas and spiced black beans can be made separately, but they come together in roughly the same amount of time. That makes this a manageable dinner for any night of the week.
Here’s what you’ll need:
- Portobello mushroom caps: Four large caps, cleaned and sliced into half-inch strips. Portobellos are the right choice here because of their size and density. They roast without shrinking down to nothing.
- Bell peppers: Three peppers in a mix of colors for flavor and visual appeal.
- Red onion: Used in both the fajita veggie mix and the black beans.
- Olive oil and lime: The base of the marinade. The lime juice helps tenderize the mushrooms as they marinate.
- Taco and Fajita Spice Blend: My homemade blend is used throughout. A store-bought fajita seasoning works as a substitute.
- Poblano and jalapeño peppers: The backbone of the spiced black beans. The poblano adds mild heat and smokiness, and the jalapeño brings a sharper kick.
- Black beans: Canned beans simmer in vegetable broth with cumin, smoked paprika, and chili powder until the liquid cooks off and the flavor concentrates.
- Vegetable broth: My homemade vegetable stock adds the best depth, but any low-sodium store-bought broth works.
Tips for the Best Mushroom Fajitas
- Don’t skip the marinade time. Even 10 to 15 minutes in the olive oil, lime, and spice mixture makes a meaningful difference in flavor. Toss the mushrooms occasionally while they sit.
- Use two sheet pans. Spreading everything into a single layer across two pans is what gets you roasted vegetables rather than steamed ones. Crowding the pan is the most common reason fajita vegetables turn out soft instead of slightly charred.
- Start the beans while the vegetables roast. The beans take about 20 minutes on the stovetop, which lines up almost exactly with the 25-minute roast time for the fajitas. Get the beans going right when the sheet pans go into the oven.
- Serve with Plant-Based Whole30 compatible toppings. Sliced avocado, fresh cilantro, sliced jalapeños, and lime wedges keep this meal compliant and add great freshness to the finished plate.
If you’re looking for other vegetarian taco night options, try my Crispy Potato Tacos. They’re stuffed with potatoes and fried until golden and delicious.
Mushroom Fajitas with Spiced Black Beans
Ingredients
For the mushroom fajitas
- 4 large portobello mushroom caps, cleaned and sliced into ½-inch strips
- 3 bell peppers, various colors, sliced
- 1 large red onion, sliced
- ¼ cup olive oil, divided
- 3 tablespoons fajita spice mix, divided
- 1 lime, juiced
For the spiced black beans
- 1 tablespoon olive oil
- ½ cup red onion, diced
- 1 poblano pepper, diced
- ½ jalapeño, diced with seeds and ribs removed
- 2 cloves garlic, minced
- 1 teaspoon kosher salt
- 1 teaspoon ground cumin
- ½ teaspoon smoked paprika
- 1 teaspoon chili powder
- 1 cup vegetable broth
- ½ lime
Instructions
Make the Mushroom Fajitas
- Preheat oven to 450 degrees F and line two large baking sheets with foil.
- Mix together 3 tablespoons olive oil, 2 tablespoons fajita spice mix and juice of 1 lime in a large bowl. Add sliced mushrooms and toss to coat. Let marinate for 10 to 15 minutes, tossing occasionally.
- Once marinated, divide mushrooms between two baking sheets. Add sliced peppers and onions to the marinate bowl with 1 tablespoon olive oil and 1 tablespoon fajita spice. Toss to combine and divide among sheet pans with mushrooms, spreading to a single layer.
- Roast for 25 minutes, rotating pans halfway through.
Make the Spiced Black Beans
- Meanwhile, prepare the black beans by heating 1 tablespoon olive oil in a medium pot. Add diced red onion, poblano and jalapeño and cook on medium-high heat for about 5 minutes.
- Add minced garlic and spices, cooking 1 more minute. Add in black beans and broth, stirring and bringing to a boil. Once boiling, reduce heat to medium and continue cooking until liquid is cooked off, about 15 minutes.
- Squeeze juice of ½ lime into beans and serve with Portobello Mushroom Fajitas and Whole30 compatible toppings of your choice – sliced avocado, sliced jalapenos, fresh cilantro and lime wedges.
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