Prepare the oven and dish: Preheat your oven to 350°F. Grease a 3-quart or 9 x 13-inch casserole dish to prevent sticking and set it aside.
Cook the pasta: Bring a large pot of water to a boil, adding 1 tablespoon of salt. Cook the pasta according to package directions until it is al dente. Before draining, reserve ½ cup of the pasta water. Once drained, toss the pasta with olive oil to keep it from clumping together.
Mix the cheese: In a large bowl, combine the shredded cheddar and mozzarella cheeses. Set aside about 8 cups of this cheese blend.
Start the roux: In a large pot or Dutch oven, melt the butter over medium heat. Once melted, whisk in the flour and cook for approximately 2 minutes, stirring constantly until the mixture turns a light golden color.
Create the cheese sauce: Gradually add the milk, heavy cream, and reserved pasta water to the roux, whisking continuously. Cook until the mixture becomes smooth and thickens slightly, about 3 minutes.
Season the sauce: Stir in the paprika, mustard powder (or Dijon mustard), garlic powder, onion powder, ½ teaspoon of salt, and black pepper. Reduce the heat to low and let it simmer for 2 to 3 minutes, stirring occasionally, until the sauce reaches a gravy-like consistency.
Incorporate the cheese: Add 3 cups of the cheese mixture to the sauce and stir until fully melted. Repeat with another 3 cups of cheese, mixing thoroughly. Add the cooked pasta to the pot and fold it into the cheese sauce until evenly coated. Taste the mixture and adjust the seasoning if necessary.
Assemble and bake: Pour the macaroni and cheese into the prepared casserole dish, spreading it out evenly. Sprinkle the remaining 2 cups of cheese over the top. Bake in the preheated oven for 15 minutes, or until the cheese topping is melted and bubbly. For a more golden crust, place the dish under the broiler for an additional 2 to 3 minutes.
Serve: Allow the baked mac and cheese to cool slightly for about 5 minutes before serving. Enjoy while warm.