Stir together 1/2 cup spaghetti sauce, ground beef, breadcrumbs, and next 4 ingredients just until combined. Shape mixture into 2 (8-inch) loaves, and place in a lightly greased 13- x 9-inch baking dish.
Bake at 350° for 25 minutes.
Stir together remaining spaghetti sauce, brown sugar, and next 3 ingredients. Pour sauce evenly over meat loaves, and bake 25 more minutes or until beef is no longer pink in center. Let stand 10 minutes before serving.