Preheat the oven to 400 F or 200 C. Cut bell peppers, onion and portobello mushrooms in long thin strips.
You can skip this step if you are using store-bought fajita seasoning. Use 2 tbsp fajita seasoning for this recipe. In a bowl combine chili powder, smoked paprika, ground garlic, dried oregano, coriander, cumin, black pepper and salt. Stir to combine.
Transfer cut veggies to the heat-proof pan. Mix with the seasoning and olive oil. Roast for 20-25 minutes until the veggies are charred. Alternatively, broil for 10 minutes.
Half and pit avocados. In a medium bowl, mash them with a fork and add ground garlic, juice of one lime and season with salt.
Drain a can of black beans. Transfer them to a bowl and microwave for 1 minute. Alternatively, warm them in a pot or skillet with a bit of liquid.
Wrap tortillas in aluminum foil and put them in the oven for 5 minutes, or microwave tortillas on a plate for about 20 seconds.
Assemble veggie fajitas. Smear guacamole, add black beans, roasted peppers, mushrooms and onions. Top with vegan sour cream, salsa and fresh cilantro. Alternatively, use other toppings like pico de gallo or chipotle corn salsa.
