2 pounds 80/20 Ground Beef Salt and Freshly Ground Pepper 8 slices Swiss Cheese
Shape ground beef into 8 patties. Season generously with salt and pepper. Cook them on griddle for 3 to 4 minutes per side, for medium. Top patties with cheese after flipping. Remove when cheese has melted and set aside.
Butter 2 tablespoons Olive oil 1 Onion (sliced)
Add two tablespoons of butter and olive oil to the griddle and add the onions. Cook until onions have softened, about 5 minutes. Remove from griddle and set aside.
1/3 cup Ketchup 1/3 cup Mayonnaise 3 tablespoons Pickle Relish
Mix together the ketchup, mayonnaise, and pickle relish.
16 slices Rye Bread
Assemble burger patties onto a slice of the bread. Top with some of the onions, and the smear of the ketchup mixture. Top with another piece of bread.
Butter (plus more to brush griddle)
Brush griddle with more butter, and place sandwich onto the griddle. Once this side is golden brown and crisp, brush butter onto the top slice of bread and then flip the sandwich over. Cook this side until golden brown and crisp and the cheese has melted. Repeat with remaining ingredients and serve.