I make smoked mac and cheese from scratch from time to time using my wife’s recipie.
You make a light roux with butter an wondera flower. Once the roux is to your liking, add milk and diced onions and once the onions start getting soft, add the cheese. Mix with cooked macaroni. Put in a pan, put an extra layer if shredded cheese on top and sprinkle with Italian breadcrumbs. Bake until it looks gorgeous. Serve with a side of Del Monte brand stewed tomatoes. This is one of my favorite winter meals.
If You put this in the smoker you will find that the smoke flavor will not make it into the center of the mac and cheese unless you stir it occasionally. My solution is to use smoked cheese when making the mac and cheese. I find a 50/50 ratio of non smoked and smoked cheese works best for me and I put a layer of non smoked cheese on top since that will get smoked anyway.
I have to admit if I’m just making smoked mac and cheese for myself, I just get a frozen Single serve mac and cheese from the supermarket and throw it in the smoker with the ribs.
I used to make a good cheap and easy “bulk feed” mac and cheese for large (50-100 people) bbqs using #10 cans of members mark cheddar cheeses sauce and milk. Unfortunately members mark cheddar cheese sauce sucks anymore so I stopped serving it.