Place breadcrumbs in a small bowl and pour over milk. Set aside.
Place mince in a large bowl. Add egg, parmesan, parsley and garlic, and season. Add breadcrumb mixture, then mix well to combine. Roll tablespoons of mixture into balls. Place on a large plate.
Heat oil in a large frying pan over medium-high heat. Cook meatballs, turning, for 5 minutes or until browned. Add pasta sauce to pan and stir to combine. Reduce heat to medium-low, then simmer, covered, for 15 minutes or until meatballs are cooked through.
Toss meatball mixture through spaghetti, and serve topped with basil leaves and extra parmesan.