Place the balls of beef on a HOT flattop grill and using a spatula smash them flat
Season the top of the smashed patties with salt and pepper
Add some sliced onion right on top of the patty
Grill until the bottom has a nice crust and then flip it over, cook an additional 1-2 minutes
Add a slice of cheese on top of each patty
Butter up the brioche buns and place alongside the patties on the grill to toast up
To assemble the burgers, put mustard and ketchup on the bottom bun, add 2 patties with cheese and onions, top with a few pickle slices and the top bun
Notes
Use an 80/20 ground beef to add flavor.American cheese works best on smash burgers, but you can also use a sharp cheddar or pepper jack cheese.Season the patties once they have been flattened on the griddle.