Cheesy Pasta Bake

Ingredients:

Instructions:
Bring salted water to a boil and cook penne according to instructions. In another pan, fry beef and onions until meat is just browned. Add mushrooms and cook until onions are translucent, about another two minutes, and then take off heat. Drain pasta and add to meat mixture, and stir in 1 ½ cups cheese. Transfer to a casserole dish, sprinkle the remaining cheese over top, and bake at 165 degrees Celsius for about twenty minutes.