Peel onions; cook in boiling salted water 30 minutes. Drain and let cool. Cut a slice of the top of each onion; remove centers. Chop centers and reserve 2 tablespoons. Combine ground beef, sausage, seasonings, mustard, bread crumbs, chili sauce, and the 2 tablespoons of chopped onion centers. Stuff onions and place in baking pan (cut a small slice off the bottom to help them stand).
Bake at 350° for 30 minutes.
Calories per serving: 279