01 -
Place a nonstick or well-seasoned cast-iron skillet over medium-low heat for 1 minute.
02 -
Spread the softened butter evenly over one side of each bread slice, covering the edges.
03 -
Place 2 bread slices buttered-side down. Top each with 2 slices American cheese, half of the grated cheddar, and a tiny pinch of black pepper if using. Close with the remaining bread, buttered-side up.
04 -
Set the sandwiches in the skillet and cook for 3-4 minutes, until the bottoms are evenly golden. Cover the pan for part of this time if the cheese is slow to soften.
05 -
Flip carefully and cook for 2-3 minutes more, pressing lightly once with a spatula, until the second side is crisp and the cheese is fully melted.
06 -
Transfer to a cutting board and rest for 1 minute. Slice in half and serve hot.