Bring a large pot of salted water to a rolling boil. Add the elbow macaroni and cook according to package directions until al dente. Drain and set aside without rinsing.

In a large saucepan or Dutch oven, melt the butter over medium heat. Once fully melted and starting to foam, whisk in the flour. Cook this roux for about 2 minutes, whisking constantly.

Slowly pour in the warm milk and heavy cream while whisking continuously. Keep whisking until the mixture is smooth and starts to thicken, about 4 to 5 minutes.

Remove the pan from heat and add the American cheese cubes first. Stir until melted, then gradually add the cheddar cheeses, Parmesan, and Romano.

Add the salt, pepper, dry mustard, and paprika. Stir until everything is melted and silky smooth.

Fold the cooked macaroni into the cheese sauce until every noodle is coated. Transfer to a greased 9x13 baking dish.

Sprinkle with additional shredded cheese if desired and broil for 2 to 3 minutes until bubbly and lightly browned. Serve immediately.