Place 1 slice of bread, butter-side down into the grill and top with one slice of cheese
Arrange the apple slices evenly over the top and place the other slice of cheese on top of the apples
Top with the remaining slice of bread, butter-side up.
Cook until the bread is golden brown, 2-3 minutes, then flip the sandwich over, and cook until the other side is golden brown and the cheese has melted, 1 to 2 more minutes.