Boil a medium pot of salted water and cook the pasta. Reserve some of the pasta water and set it aside.

Heat a large pan with butter or oil. Add the white onion and garlic, cooking until the onion becomes translucent. Add the pepperoni and tomato, cooking for another minute. Then, add the garlic powder, onion powder, and parsley.

Drain any excess oil from the pan and add the cream. Cook until the sauce starts to bubble. Stir in both cheeses and the reserved pasta water, mixing until thickened.

Add the cooked pasta and green onions to the sauce, stirring until the pasta is well-coated. Serve with Parmesan on top and enjoy!