Preheat oven to 400°F. Bring a large pot of salted water to a boil. Add the macaroni noodles and cook until al dente according to package directions. Drain well and return to the pot.
1 pound macaroni noodles
Meanwhile, melt the butter in a large saucepan over medium-high heat. When the butter is completely melted, sprinkle the flour over the butter and whisk in to form a roux. Cook for 1-2 minutes until bubbly.
1/2 cup salted butter, 1/4 cup all-purpose flour
Gradually whisk in the milk, onion powder, creole seasoning, salt, pepper, and paprika, then continue to cook, whisking frequently until slightly thickened, around 3-5 minutes.
3 1/2 cups milk, 2 teaspoons onion powder, 1 teaspoon creole seasoning, 1 teaspoon kosher salt, 1/2 teaspoon black pepper, 1/4 teaspoon paprika
Sprinkle 1/4 of the cheese over the sauce and whisk it in until melted. Repeat with another 1/4 of the cheese.
16 ounces cheese
Pour the sauce over the drained pasta and stir to coat.
Add 1/2 of the macaroni and cheese sauce to a 9x13-inch pan. Arrange 4 slices of cheese on top and sprinkle with another 1/4 of the shredded cheese. Spread the remaining pasta and sauce on top and sprinkle with the remaining cheese.
Bake for 10-20 minutes until cheese it melted on top and everything is hot throughout.