Meatballs: combine the ground beef mince, panko bread crumbs, garlic, dried onion, dried parsley, dried basil, salt, pepper and egg in a medium sized mixing bowl. Use a tablespoon and clean hands to portion, roll into balls and place on a clean chopping board.
Cook meatballs: add olive oil to a large sauté pan and turn to hight heat. Use kitchen tongs to gently place the meatballs into the pan. Cook the meatballs, using a wooden spoon to rotate until all sides are browned and crispy (around 8 to 10 mins). Then use kitchen tongs to remove meatballs and place on a paper towel lined chopped board. If there is lots of excess oil in the pan, use paper towel to absorb this liquid before starting the sauce.
Tomato sauce: without rinsing the pan, add the passata, diced tomatoes, tomato paste, Worcestershire sauce, dried onion and Italian herbs to the pan. Use a wooden spoon to stir and combine.
Meatballs and sauce: use kitchen tongs to transfer the cooked meatballs back into the sauce. Use a wooden spoon to gently stir and cover the meatballs in the sauce. Turn the heat to low and allow the dish to simmer for 15 mins, stir occasionally during this time.
Let cool: once done, turn the heat off and allow the meatballs and sauce to cool. Use this time to prepare the buns.
Buns: use a knife to cut each bread roll open.
Filling: use a spoon to spoon sauce into each bread roll, then scoop 3 to 4 meatballs in, followed by a couple more spoonful's of sauce on top. Then place open side up in a baking dish. Repeat for the other subs.
Cheese: sprinkle grated cheese on top of each sub, then transfer the baking dish into the middle rack in the oven.
Bake: cook the subs until the cheese melts, which will take between 5 to 10 mins.
Serve: once cooked, use oven mits to remove the baking dish from the oven and place on a heatproof surface. Use kitchen tongs to transfer the subs to individual plates, then sprinkle basil leaves over the top.