Preheat the oven to 375 degrees F. Line a baking sheet with parchment paper.
Place the meat in a mixing bowl and sprinkle with salt and pepper. Trim the crusts off the bread and place in a small bowl, cover with milk and soak to soften. Squeeze the milk from the bread and crumble as you add it to the meat. Then add the eggs, cheese, parsley, grated onion and garlic, and mix to combine. Form into a loaf about 4 inches high and put on the baking sheet. Spray with olive oil.
Mix the ketchup with the balsamic drizzle and Worcestershire. Season with pepper. Spread about 1/3 cup of the ketchup mixture over the top of the meatloaf. Bake until cooked through, about 1 hour.
To reheat, slice the meatloaf 1 1/2 inches thick and put in a pot of warmed chicken stock. Serve the meatloaf hot or cold on thick-sliced Italian white bread with the remaining ketchup mixture and the lettuce, tomato, onions, mozzarella and basil.