Traeger Meatball Sub Casserole

"If you love meatball subs, you are going to love my Traeger Meatball Sub Casserole! Italian meatballs, homemade marinara, all the cheese you can throw on it, and a fresh hoagie roll are a match made in meatball heaven. Homemade meatball subs are kind of legendary around here, but when you are cooking for a bunch of people, as we do, they are also kind of a pain. There are the meatballs and the cheese covering and then the final bake to melt the cheese. UGH. "