Ingredients
4 tbsp. butter
8 slices country white bread, 1/2" thick
16 slices American cheese
1 lb. 80-percent lean ground beef, chilled
kosher salt
Freshly ground black pepper
Ketchup, for serving
Preparation
Step 1Preheat oven to 350°. Spread butter evenly on one side of each piece of bread, then place bread buttered side down in a cast-iron skillet over medium-high heat until golden brown. Transfer to a large sheet pan with toasted side down and place 2 pieces of American cheese on each piece of bread.Step 2Preheat same cast iron pan over high heat. In a mixing bowl, add cold ground beef and season with salt and pepper. Divide into 1/4-lb. burgers and form 1/2"-thick, square-shaped patties, similar to bread dimensions. (Avoid over-handling burgers as it will make them tough.) Cook burgers in two batches; flip burger after 2 minutes, then cook 2 minutes more. Transfer to a plate and loosely cover with aluminum foil; rest 2 minutes.Step 3Meanwhile, place sheet pan with bread in the oven until cheese is just melted. Lightly blot burgers with a paper towel, then place burgers on toasted bread with cheese and top with second piece of bread.Step 4Return grilled cheese burgers to the cast iron pan to warm the bread. Serve immediately, with ketchup.
