Butter one side of each slice of bread. Place all slices butter-side down. Spread jam on one slice per sandwich, then divide the cheese between the two sandwiches. Close both sandwiches by topping each with its remaining slice.
Heat a non-stick or cast-iron skillet over medium heat. Add sandwiches to pan. Gently press sandwiches with spatula as they cook. Cook 2-4 minutes on each side, flipping often to avoid burning, until cheese melts and bread is toasted.
