Start by washing and slicing your portobello mushrooms into strips. Next, slice your bell peppers and onion into similar-sized pieces for even cooking.
In your large skillet, heat the olive oil (or water/broth) over medium heat. Add the sliced onions first, sautéing for about 2-3 minutes until they start to become translucent.
Toss in the portobello mushrooms and bell peppers. Sprinkle the taco seasoning over the mixture and stir well. Cook for another 5-7 minutes, stirring occasionally until the vegetables are tender and the mushrooms have released their delicious juices.
Remove the skillet from heat and drizzle the fresh lime juice over the sautéed veggies. Give it a good toss to combine all the flavors.
While the veggies are cooking, wrap your corn tortillas in foil and place them in a preheated oven at 350°F (175°C) for about 10 minutes, or heat them on a skillet for a few seconds on each side until warm.
To serve, place a generous scoop of the portobello and pepper mixture onto each tortilla. Top with your favorite toppings such as avocado slices, guacamole, salsa, vegan cheese, and a sprinkle of nutritional yeast.
