Preheat griddle or skillet to medium/medium high heat.
Generously butter one side of each slice of bread. Place buttered side down in skillet, then layer on all three slices of cheese. Place remaining slice of bread on top, butter side up.
Grill about 4 minutes, until bottom is golden. Flip sandwich over carefully, and continue grilling. Press sandwich with a spatula, watching for the bottom to brown. Cover as needed to help melt cheese thoroughly.
Once golden on both sides, remove from heat and let set for a minute. Cut in half and garnish as desired. Enjoy immediately!