Preheat smoker to 250°F (or oven to 350°F if not smoking).
Bring a large pot of salted water to boil. Cook macaroni for 5–6 minutes until just shy of al dente. Drain and set aside.
In a saucepan, melt butter over medium heat. Whisk in flour to form a roux; cook for 2 minutes.
Slowly whisk in milk. Simmer and stir until thickened, about 3–4 minutes.
Stir in salt, pepper, smoked paprika, and garlic powder.
Remove from heat. Stir in ¾ of the cheddar and gouda until melted and smooth.
Fold in the cooked macaroni until evenly coated.
Pour into cast iron skillet or baking dish. Top with remaining cheese.
Place in smoker for 30–40 minutes, or bake in oven for 25–30 minutes until bubbling and golden.
Serve hot, optionally with coleslaw or barbecue meats.
