Preheat your smoker to 225°F (107°C).

Cook macaroni according to package instructions; drain and set aside.

In a large pot over medium heat, melt 4 tablespoons butter. Whisk in the flour and cook for 1–2 minutes.

Gradually whisk in milk and heavy cream. Cook, stirring, until slightly thickened.

Stir in cheddar, gouda, and Parmesan until melted and smooth. Add garlic powder, onion powder, smoked paprika, salt, and pepper.

Fold in the cooked macaroni until evenly coated.

Pour the mixture into a greased 9×13-inch aluminum pan.

For a crunchy topping, combine panko and melted butter and sprinkle over the top.

Place the pan in the smoker and smoke uncovered for 1 hour, or until bubbling and golden.

Let cool slightly before serving for the creamiest texture.