Make the roux; in a large pot over medium heat, melt ¼ c butter and then whisk in ¼ c flour.
Add 4 oz cream cheese and 4 c whole milk. Simmer for 5 minutes to thicken. Whisk in 3 c Gouda cheese, 1 tbsp Dijon mustard, 1 tsp hot paprika, and ½ tbsp ground black pepper. Simmer for 5 to 10 minutes to melt the cheese.
While the sauce is cooking, in a pot of boiling water cook 5 c macaroni.
Turn off the heat and add the cooked macaroni to the cheese mixture.
Transfer to a large foil pain or a cast iron dutch oven. Top with ¼ c Parmesan cheese and ⅓ c bread crumbs.
Place in the smoker and smoke for 1 hour.
Remove from smoker, top with ¼ c chives, and serve.
Notes
You can stir the mac and cheese occasionally while cooking on the grill to give it a more smokey flavor. Additionally, I prefer to make this in a cast iron dutch oven. It seems to add more flavor and provides a better cook.