Preheat the oven to 375F.

Mix the beef, breadcrumbs, egg, and half the Parmesan, then roll into meatballs.

Brown the meatballs in a skillet, then transfer to a baking dish.

Pour the marinara over the meatballs and top with mozzarella and remaining Parmesan.

Bake 22-25 minutes until the cheese is bubbly and the meatballs are cooked through.

Garnish with basil and serve.