In a large bowl, combine cooked spaghetti, melted butter, Parmesan cheese, mozzarella cheese, Romano cheese, garlic powder, onion powder, salt, pepper, and Italian seasoning.
Mix until evenly combined.
Pour spaghetti mixture into a 9-inch pie dish.
Bake for 25 minutes, or until the top is golden brown.
Let cool for 10 minutes before serving.
Interesting Facts
This Three-Cheese Spaghetti Pie is a great way to use up leftover spaghetti.
You can substitute the Parmesan cheese for any type of cheese you like.
This dish can be served as a main course or as an appetizer.