In a large bowl, beat egg with salt, italian seasoning, red pepper flakes, and garlic. Add chopped onion, beef, turkey, bread crumbs, and parmesan cheese; mix well. Shape mixture into 3 cm balls and brown in a large skillet. Drain meatballs and transfer to a 5 litre crockpot.
In the same bowl, mix tomato sauce and wine; pour over meatballs. Cover and cook on Low for 5.5 to 6 hours.
To serve: place 3 to 4 meatballs in each split roll; top with sauce from crockpot. If desired add condiments and serve.
6-8 Servings.