In A Bowl, Combine The First Seven Ingredients. Crumble Beef Over Mixture And Mix Well. Shape Into Four Patties. For The Barbecue Sauce, Combine Ketchup, Brown Sugar And Mustard In A Small Bowl. Grill Patties, Uncovered, Over Medium-Hot Heat For 3 Minutes On Each Side. Brush With Barbecue Sauce. Grill 4-6 Minutes Longer Or Until Juices Run Clear, Basting And Turning Several Times. Serve On Buns.