1 tablespoon plus 1 teaspoon kosher salt
¾ pound cavatappi, rotini, or fusilli
3 cups half-and-half
2 large eggs
1 ½ cups (6 ounces) shredded extra sharp Cheddar
1 cup (4 ounces) shredded mozzarella
1 cup (4 ounces) shredded Monterey Jack
8 ounces Velveeta, cubed
¾ cup (1 ounce) freshly grated Parmigiano-Reggiano
1 cup milk
2 teaspoons dry mustard 1 teaspoon garlic powder
1 teaspoon onion powder ½ teaspoon paprika
1 teaspoon freshly ground black pepper 6 bacon slices, cooked and crumbled
Preheat the oven to 350°F. Bring a large pot of water to a boil. Add 1 tablespoon of the salt and the pasta and cook until tender but still firm to the bite, 8 to 10 minutes. Drain the pasta in a colander and set aside.
While the pasta is cooking, heat the half-and-half in a large saucepan over medium heat. Just before the mixture starts to boil, remove the pan from the heat and let cool for 5 minutes. Whisk the eggs in a bowl, then whisk in 2 cups of the warm half-and-half. (This will keep the eggs from scrambling.)
Pour the egg mixture into the saucepan and whisk to combine. Stir 1 cup of the Cheddar, all the mozzarella, Monterey Jack, Velveeta, and Parmigiano-Reggiano, and the milk into the saucepan. Heat the saucepan on medium-low heat to help melt the cheese. Whisk in the mustard, garlic powder, onion powder, paprika, the remaining 1 teaspoon salt, and the pepper. Do not let the mixture boil.
Toss the cooked pasta and cheese sauce together and then pour into a 4-quart baking dish. Top with the remaining 1/2 cup Cheddar. Bake for 20 minutes. Sprinkle an even layer of crumbled bacon on top and bake for 10 minutes more.