Step 1 Heat a cast-iron pan or griddle over low heat. Brush one side of each bread slice with the melted butter.
Step 2 Spread half the cheese evenly over the unbuttered sides of two slices of bread, carefully spreading it to the edges. Spread 1 tablespoon of apple butter over each of the unbuttered sides of the two remaining slices, then place them, apple-butter side down, onto the slices spread with cheese.
Step 3With a spatula, place a sandwich into the heated pan and weight it with a second heavy pan or a steak weight. (If your pan is large enough, cook both sandwiches; otherwise, cook them one at a time.) Cook until golden brown, about 3 to 4 minutes. Flip the sandwich and weight it with the pan or steak weight, and cook until golden brown, another 3 to 4 minutes.
Step 4Remove the sandwich to a cutting board and cut it in half or quarters. Serve immediately, with extra apple butter if desired.