Bring a large pot of salted water to a boil. Add 1 pound of pasta and cook it for about 6 minutes—slightly firm, since it will finish in the oven. Drain well and fold in 2 tablespoons of butter to keep it from sticking.
In a saucepan, melt the remaining 2 tablespoons of butter. Stir in ¼ cup grated onion, 3 crushed garlic cloves, 1 teaspoon smoked paprika, and 1 teaspoon cayenne pepper. Cook until the onion softens and everything smells flavorful.
Sprinkle in 4 tablespoons of flour. Stir for about 1 minute so the flour cooks out and blends with the butter and spices.
Slowly whisk in 2 cups of half-and-half until smooth and slightly thickened. Stir in 1 tablespoon Worcestershire sauce and 4 ounces of cream cheese until melted and creamy.
Add 16 ounces grated deli American cheese and 16 ounces grated mild cheddar, a handful at a time, stirring until smooth and fully melted.
Take the sauce off the heat and fold in the pasta until well coated. In a greased baking dish, add half the pasta mixture, sprinkle 8 ounces shredded mozzarella, then add the rest of the pasta. Top with a handful of sharp cheddar.
Bake at 400°F (200°C) for 20 minutes, until bubbly and golden on top. Let it rest for 5 minutes, then serve your creamy Pepper Belly Pete Copycat Mac and Cheese while it’s warm.