Barbecue Beef Brisket

6-pound beef brisket
2 large onions, sliced
2 cloves garlic, minced
3/4 cup brown sugar
1/2 cup vinegar
1 cup ketchup
2 tablespoons teriyaki sauce

Remove all fat from brisket. Place brisket in a heavy skillet and brown on both sides. Add onions and garlic and brown. Add remaining ingredients. Cover and simmer 4 hours until very tender. serves 6-7.