Sure do...DH just made some delicious ones last week. Brown your ground beef with onion, salt and pepper. Drain well. Add enough water to cover meat and simmer...the longer the better.
Spread mustard on a bun if you wish, spoon on meat, then put sandwich in skillet on medium high, mash with a spatula and warm on both sides.
Kim always cuts up some extra onion which he likes on his...I have mine without.