Saute mushrooms in butter, cover and set aside. Prepare vegetables and cheese. Break apart the meat in a skillet and saute until browned. Add taco seasoning and water, stir until combined. Put meat in the middle of each tortilla, layer other ingredients on top. Fold top and bottom ends of the tortilla toward the center and roll up sideways, starting from one side.
Vegetarian version:
To replace beef, combine substituted ingredients in a pot and heat.