Start by boiling a large pot of salted water. Add 1 pound of elbow macaroni and cook according to package instructions until al dente, about 7-8 minutes. Drain and set aside.

In a medium saucepan, melt 1 stick of butter over medium heat. Whisk in 1/2 cup of all-purpose flour, cooking for 1 minute until pale and bubbly. Gradually pour in 3 cups of whole milk and 1 cup of heavy cream, whisking constantly until thickened, about 5-7 minutes.

Stir in 4 cups of sharp cheddar and 2 cups of Gruyere cheese until melted, then season with 1/2 teaspoon salt, 1/4 teaspoon pepper, 1/4 teaspoon paprika, 1/4 teaspoon garlic powder, and 1/4 teaspoon onion powder.

In a large mixing bowl, combine the drained macaroni with the creamy cheese sauce, ensuring all pasta is coated.

Preheat your oven to 375°F (190°C). Grease a 9x13 inch baking dish. Pour the macaroni and cheese mixture into the prepared dish, spreading it evenly. If desired, mix 1 cup of panko breadcrumbs with a tablespoon of melted butter and sprinkle on top.

Place the baking dish in the oven and bake for 20-25 minutes until golden brown and bubbly.

Let it sit for about 5 minutes before serving, to help it set.