Combine the ground beef and onions in a large skillet and cook over medium
heat, breaking up the chunks with a wooden spoon, until the meat is browned,
about 10 minutes. Drain off the excess fat. In a small mixing bowl, stir
together the ketchup, brown sugar, vinegar, Worcestershire, mustard, and honey
if using until well combined. Stir the sauce mixture into the meat and onions
and bring to a simmer. Serve on hamburger buns.
