Add the onions and cook for 3-4 minutes or until softened. Add the mushrooms and continue cooking for 2-3 minutes. Add the garlic and cook for 1 minute. Season with salt and pepper.
Add the beef and use a wooden spoon to break it up into pieces. Brown the beef while stirring. Season with salt and pepper.
Add the tomato sauce and mix well. Check for seasoning and make the necessary adjustments.
Assembly
Preheat oven to 400 degrees F.
In a large baking dish, empty the bag of frozen Celentano Cavatelli. Add the beef and mix well.
Top with cheese and cover with foil.
Bake for 20 minutes. Uncover and bake for 5-10 minutes or until cheese has browned and mixture is bubbly.