Add all of the meatball ingredients except the oil and mix to combine. Roll the meatballs into balls (the size is your preference). Note: The bigger they are, the longer they’ll take to cook.
Place a pan over medium-high heat, add olive oil and sear the meatballs for 5-6 minutes, rotating frequently until all sides are browned. Remove and set aside.
Add the onions and sauté in the same pan for 3-4 minutes or until slightly translucent. Add garlic and cook for 1 minute.
Add crushed or diced tomatoes, a splash of water to rinse the can, tomato passata, torn or chopped basil leaves, and a good seasoning of salt and pepper. Bring to a boil, reduce heat to low, and simmer for 15-20 minutes. If you like to add sugar, do this now.
Add the meatballs and resting juices to the sauce and cook for 1-2 minutes or until the meatballs are hot in the centre. Check and adjust the seasoning.
Preheat oven to 200℃-390℃ on the grill or broiler setting.
Slice your rolls and lather with butter or extra virgin olive oil (optional). Spread with basil pesto (optional), add slices of fresh mozzarella, and place in the oven to toast and melt. If your cheese doesn’t melt to your liking, you can use a blowtorch.
Place the meatballs on the opposite side of the toasted roll and top with marinara sauce, freshly grated Parmigiano Reggiano, basil leaves and cracked black pepper. Close the roll, slice and dig in.