In a large skillet, cook turkey and onion over medium heat 6-8 minutes or until turkey is no longer pink, breaking up turkey into crumbles; drain if necessary. Add garlic; cook 1 minute longer. Stir in sugar, flour and pepper until blended.
Stir in ketchup, Worcestershire sauce, mustard and barbecue sauce. Bring to a boil. Reduce heat; simmer, covered, 10 minutes to allow flavors to blend. Spoon meat mixture onto bun bottoms; replace tops. Freeze option: Freeze cooled meat mixture in freezer containers. To use, partially thaw in refrigerator overnight. Heat through in a saucepan, stirring occasionally and adding a little water if necessary.