In the bowl of a food processor with the machine running, drop through the feed tube the garlic, cheese, and parsley. Process until the cheese is finely grated. Add the slice of bread and process until fine crumbs. Transfer the mixture to a large bowl and blend well with the beef, sausage, bread crumbs, egg, tomato paste, red wine, salt and black pepper. Shape the mixture into 2-inch balls (I use a 2-ounce ice cream scoop), about 48 meatballs. Dredge the meatballs in the flour, shaking off the excess. Heat 2 tablespoons of the oil in a large skillet over medium-high heat. Add about ¼ of the meatballs and cook until the meatballs are browned on all sides, but not cooked through. Transfer the meatballs to the sauce and continue with the remaining meatballs adding extra oil as needed. Cook the meatballs in the sauce, stirring occasionally, until the sauce has reduced, darkened in color, and thickened, about 3-4 hours.