Set a large sauté pan to medium-high heat. Pour in oil. Add mushrooms when pan is hot and cook for about 3-5 min, until all the liquid released by the mushrooms has evaporated and they are golden brown
Remove mushrooms from pan.
Add onion into the pan and cook for 2-3 min. until slightly browned. Add garlic and peppers. Cook for 3-4 min. more or until the peppers are tender.
Place mushrooms back in the pan. Pour in soy sauce. Season with salt and pepper. Cook for 1-2 min.
Serve with tortillas, guacamole and roasted tomato salsa.
Feel free to add any variety of mushrooms or make your own combination.