Instructions

1. Place the slices of bread in a large bowl. Pour the milk over the top and let them sit for about 5 minutes to let the milk soak into the bread.
2. Meanwhile, heat 1 tablespoon of the oil over medium-high heat in a skillet. Add the onions and cook until tender. Add the garlic the last 30 seconds of cooking. Remove from the heat to cool slightly.
3. Once the milk has soaked into the bread, use your hands or a masher to crumble the bread.
4. To that same bowl, add the ground beef, sausage, egg, parmesan, parsley, salt, paprika, oregano, and cooked onion mixture. Use your hands or a wooden spoon to gently combine everything, being careful to not overwork the meat.
5. Using a 1 tablespoon scoop (or your hands) divide the mixture into about 30 meatballs. Use slightly wet hands to roll them into balls.
6. Heat the remaining tablespoon of oil in a large skillet over medium heat. Working in 2 or 3 batches, add the meatballs to the skillet and cook until browned on all sides. This should only take about 5 minutes per batch – they will not be cooked through all the way. Remove the meatballs to a plate and repeat with the remaining meatballs.
7. When all of the meatballs have been browned, return them all to the skillet. Add the marinara sauce and stir gently to coat. Turn the heat down to medium-low and let the meatballs simmer in the sauce, uncovered, for about 15 minutes.
8. Turn the oven on to broil.
9. Place your rolls on a large baking sheet and open up. Place 2 slices of cheese on each roll.
10. Broil until the cheese has melted and the buns are toasted. Watch them carefully, as this will only take a minute.
11. Add some of the meatballs and sauce to each roll and serve.