Directions
Spread the softened butter evenly over one side of each bread slice. Place 4 bread slices butter-side down on a work surface. Divide the cheddar cheese and mozzarella cheese among the slices, then top with the remaining bread slices butter-side up. Heat a large skillet over medium-low heat. Cook the sandwiches for 3 to 4 minutes per side, pressing gently with a spatula, until the bread is golden and the cheese is melted. Rest for 1 minute before slicing and serving.