2/3 cup shredded plant-based cheese or sprinkle with some nutritional yeast (optional)
1/3 cup fresh cilantro (lightly packed)
2 tablespoons fresh parsley (lightly packed)
1/2 lime (juiced)
2 tablespoons water
sea salt and black pepper
Prepare the vegetables:
De-stem the mushrooms and gently remove the gills using a spoon. Slice the mushrooms into ½-inch thick strips.
Cut off the tops of the poblano peppers, slice them in half and remove the seeds and membranes. Slice the peppers into ½-inch thick strips, up to 3-inches in length.
Slice off the root end and the tip of the red onion. Set it on one of its flat sides and cut down through the middle of the onion, then slice each half into 1/2-inch wide strips by slicing from one flat side to the other.
Toss the mushroom slices, poblano pepper slices and onion slices into a large bowl.
In a small bowl, whisk together the marinade ingredients until emulsified.
Pour the marinade over the bowl of prepared veggies. Toss well to evenly distribute the marinade. Let the veggies soak up the marinade for 30 minutes or so, tossing occasionally.
In the meantime, make the avocado sauce.
In a food processor, combine the avocados, cilantro, parsley, lime juice and water.
Blend, and add sea salt and black pepper to taste.
Transfer the sauce to a small serving bowl.
In a large skillet, heat a tablespoon of olive oil over medium heat. Once it’s shimmering, pour in the marinated vegetables. Cook, stirring occasionally, until the peppers are tender and the mushrooms are browning on the edges (ten minutes or more). Add more oil and reduce the heat if necessary; you don’t want the pan to start smoking. Remove from heat.
Gently warm the tortillas individually in a lightly oiled pan over medium-low heat, flipping halfway through cooking (about 20 seconds per tortilla). Stack the warmed tortillas on a plate and keep them warm under a tea towel. Serve the fajita filling with tortillas, avocado sauce, plant-based cheese, and hot sauce.