Cook the Pasta. Bring a large pot of water to a boil. Salt generously and cook the elbow macaroni until just al dente, about 7-8 minutes. Drain and set aside.
1 Pound Elbow Macaroni
Make Creamy Cheese Sauce. In a large saucepan over medium heat, melt butter. Whisk in the flour and cook for 1 minute.
1/4 Cup Butter, ¼ Cup Flour
Slowly whisk in the whole milk until the mixture thickens slightly, about 3-5 minutes.
2 Cups Whole Milk
Reduce heat to low and stir in the salt and ground paprika.
1/2 Teaspoon Salt, ¼ Teaspoon Ground Paprika
Add the egg yolk and whisk quickly to incorporate.
1 Large Egg Yolk
Stir in all the cheeses—cheddar, Colby Jack, white cheddar, parmesan, Romano, and American—until fully melted and smooth. This combination of cheeses gives the sauce its rich flavor and better taste than store-bought.
1 Cup Sharp Cheddar Cheese, 1 Cup Colby Jack Cheese, 1/2 Cup White Cheddar, 1/4 Cup Parmesan Cheese, 1/4 Cup Romano Cheese, 4 Slices American Cheese
Assemble and Bake. Preheat oven to 375°F.
Combine the cooked pasta and sauce in a large bowl. Stir until fully coated.
Pour into a prepared baking dish, cover loosely with aluminum foil, and bake for 15–20 minutes until hot and golden brown on top.