Preheat oven to 450 degrees.
Butter one side of 6 slices of bread and place each butter-side down on a half sheet pan. Layer 1-2 slices of cheese on each slice of bread. Spread butter on 6 remaining slices of bread and place them buttered-side up on top of the cheese.
Bake for 5-6 minutes, flip the sandwiches over, and bake for an additional 5-6 minutes, until golden brown. Baking time may vary slightly depending on the type of bread used.
