I've always loved a good meatball sub/hoagie. I recently tasted the finest meatball sub I've ever had--- and I made it myself! very simple, here's how.
For meatballs, I prefer a mixture of ground beef and hot italian sausage. In any case, beef and pork should be represented. only a minimum of bread crumbs should be used, if any. let the meatballs chill in the fridge to firm up.
I start by sauteeing onions and peppers in a skillet with olive oil. To make it simple, I use a jar of good sauce (skip the Ragu) and simmer it all together. Let simmer.
grill the meatballs over coals and wood. The wood is most important--- preferably oak or hickory. when finished remove meatballs from grill and place in simmering sauce. simmer for as long as you can stand the smell (about 30 minutes or an hour).
place meatballs (I slice mine in half, as bigger meatballs are easiest to handle on the grill) into sub roll, top with sauce, lots of fresh basil leaves, and mozzarella cheese. The flavor of the meat and sauce only improves with time--- the smokiness is suprisingly satisfying, even for those who don't care for smoke so much.