In a large skillet, heat 2 tablespoons olive oil over medium-high heat. Add the beef, half of the onion and the jalapenos; season with salt and pepper. Cook until the beef is browned and the onion is softened, 7 to 10 minutes. Transfer to a bowl; reserve the skillet.
Meanwhile, in a large bowl, combine the remaining onion, the avocados and lime juice; season with salt and pepper.
In the reserved skillet, heat the remaining 1 tablespoon olive oil over medium heat. Add the mushrooms and garlic, season with salt and pepper and cook until golden, 7 to 9 minutes; stir into the beef mixture and cover with foil to keep warm.
Wipe out the skillet and return to medium heat. Working with 1 tortilla at a time, lightly toast on both sides for about 1 minute. Stuff the tortillas with the beef mixture and avocado salad.
One Quick Hack for Dicing Avocados
