01 -
Stir the softened butter, mayonnaise, garlic powder, and a small pinch of salt until smooth and spreadable.
02 -
Spread the butter mixture on one side of each bread slice. Place 2 slices butter-side down on a board, then layer cheddar, American cheese, and mozzarella over the plain side. Top with the remaining bread, butter-side up.
03 -
Warm a large skillet over medium-low heat. Add the sandwiches and cook for about 4 minutes, until the bottom is golden and crisp.
04 -
Flip carefully and cook for 3-5 minutes more, adjusting the heat as needed, until the second side is golden and the cheese is melted through.
05 -
Transfer to a board and rest for 1 minute. Slice diagonally and serve while the cheese is hot and gooey.