Cheese Stuffed Meatball Sub

Ingredients

• 1 pound ground beef
• 1 pound ground pork
• 1 large egg, beaten
• ½ cup grated parmesan cheese
• 2 tablespoons flat-leaf parsley, chopped
• 2 teaspoons salt
• ½ teaspoons black pepper
• ½ cup milk
• ½ cup fine dry breadcrumbs
• 2 cloves garlic, minced
• ¼ cup onion, finely chopped
• 4 ounces mozzarella cheese, cut into ½ in cubes
• ¼ cup butter, melted
• ½ teaspoon garlic salt
• ½ teaspoon parsley, finely chopped
• 4 hoagie rolls
• 16 slices provolone cheese
• 1 cup marinara sauce