Preheat the oven to 375°F and grease a 9x13-inch baking dish.
Boil the elbow macaroni in well-salted water until about 1 minute short of al dente. Drain and set aside.
In a saucepan, melt 3 tablespoons of butter over medium heat. Whisk in the flour and cook for 1 minute until pale golden and fragrant.
Slowly whisk in the whole milk and heavy cream. Simmer for 3–4 minutes, whisking constantly, until thickened enough to coat the back of a spoon.
Remove the saucepan from the heat. Whisk in the cheddar, gouda, and Monterey jack in three batches, fully melting each batch before adding the next.
Stir in the smoked paprika, garlic powder, onion powder, dry mustard, salt, and pepper.
Fold the drained macaroni into the cheese sauce until fully coated.
Pour the mixture into the prepared baking dish and spread into an even layer.
Toss the panko breadcrumbs with the melted butter and scatter evenly over the top.
Bake for 20–25 minutes, until bubbling at the edges and the panko is deep golden brown.
Let rest for 5–10 minutes before serving.