Photo: A Commons contributor (CC BY 4.0) via Wikimedia Commons · source
A New York bodega classic: ground beef and onions chopped on the griddle with American cheese melted right in, scooped onto a hero with lettuce, tomato, ketchup and mayo. Fast, cheap, perfect.
Toast the rolls (2 min): Split the rolls, butter the insides and toast them cut side down on a hot griddle or skillet until golden. Set aside.
Cook the onions (3 min): In the same pan over medium-high heat, cook the onion in a little oil until soft and starting to brown.
Chop the beef (5 min): Add the beef in one flat patty, season, and let it brown hard 2 minutes. Then chop it into small crumbles with the edge of a metal spatula, mixing in the onions, until cooked through.
Melt the cheese (1 min): Push the meat into two long piles the length of your rolls, lay 2 slices of cheese over each, splash a spoon of water beside them and cover 30 seconds until melted. Chop the cheese in.
Build (2 min): Spread the rolls with mayo and ketchup, add lettuce and tomato, then slide each pile of beef in with the spatula. Wrap in paper and cut in half.
Tips
Real American cheese melts best; a sharp cheddar breaks and gets oily.
Add chopped jalapeño or hot sauce to the beef for a spicy one.