1. Butter one side of each piece of bread. Place one fourth each of ham and cheese between 2 unbuttered sides. Trim away any excess ham and cheese. Form 4 sandwiches.
2. Preheat a griddle or large cast-iron frying pan over medium-low heat. Grill sandwiches, turning once, 5 to 7 minutes, or until cheese has melted and bread is golden brown. To serve, cut each sandwich into halves or quarters.