Preheat grill to 550 degrees F with flat top cast iron griddle on top of the grill grates
Divided ground beef into 8 equal chunks and form into balls. Don’t overwork the beef
Once flat top griddle is hot, place onion slices on griddle. Season with Weber Gourmet Burger seasoning. Place one rolled ball of ground beef in the middle. Smash down into the onions until flat. Season again with Weber Gourmet Burger seasoning and flip
With the cooked onions now facing up, place a slice of cheese on top and let it melt. Once cooked a melted, remove from griddle and repeat with the rest of the onions and burger balls
