You will need meatballs and spaghetti sauce. You can use homemade meatballs and sauce or go the easy route and use pre-packaged of both. I just had a baby, so I chose pre-packaged... Okay, so I'd probably choose pre-packaged even if I hadn't just had a baby!
After your meatballs are cooked through preheat your broiler. Spoon the saucy meatballs onto hoagie buns, sprinkle with shredded mozzarella cheese and broil. I added on sauteed mushrooms and caramelized onions, not because they are necessary, but because I had them in the fridge. If I wasn't saving the bell pepper in the fridge for Cinco de Mayo, I'd probably have sauteed it and used it, too. The first time we made these it was strictly meatballs, sauce and cheese and they were good enough to make again!