Brown the ground beef in a pan. Remove the beef and drain most of the fat
Sautee diced onion and minced garlic in the beef fat over medium low heat, using the liquid expressed from the onions to deglaze the pan.
Once the onions are soft, translucent, and lightly browned (10 minutes), return beef to pan along with sugar, ketchup, and soy sauce. Add a splash of water, just enough for the ingredients to mix together easily
Simmer until liquid is reduced enough that if you run a silicon spatula along the bottom of the pan, it stays dry, without liquid immediately seeping back in (see photo). Taste and season
Serve 2-3 tablespoons full with a slice of American cheese between 2 slices of buttered white bread, pressed in a flying saucer-shaped sandwich iron.