Barbecue Meatballs

Name: Barbecue Meatballs
Ingredients: 2 cups barbecue sauce; 2 tablespoons white vinegar; 1 tablespoon loosely packed brown sugar; 1 teaspoon hot sauce; 1 teaspoon Worcestershire sauce; One 25-count bag All-Purpose Meatballs (still frozen is fine), recipe follows; Mashed potatoes, for serving; Chopped fresh parsley, for serving; Green salad, for serving; 5 pounds ground beef; 1 1/2 cups plain breadcrumbs; 1/2 cup milk; 1/4 cup heavy cream; 1/4 cup chopped fresh flat-leaf parsley; 2 tablespoons grainy mustard; 1 teaspoon salt; 1 teaspoon freshly ground black pepper; 1/2 teaspoon red pepper flakes; 4 large eggs; 2 tablespoons olive oil