Start by preheating your oven to 350°F and greasing a 9x13 baking dish.
Boil a large pot of salted water and cook the macaroni until al dente, about 8-9 minutes, then drain.
Mix milk and heavy cream in a cup, and set aside for the cheese sauce.
Melt butter in a pot, whisk in flour for 1-2 minutes, then gradually add the milk mixture, simmering until thick.
Off the heat, blend in 2 cups of cheese and the BBQ sauce, seasoning with salt and pepper to your liking.
Combine the cheese sauce with the macaroni, stir in 1 cup of BBQ meat, and transfer to the baking dish.
Top the macaroni with the remaining BBQ meat, extra BBQ sauce, and cheese, then bake for 15-20 minutes.
For a golden top, broil for 3-4 minutes, then let it cool for 10 minutes before serving.