Preheat a cast iron or nonstick pan over medium-low heat.
Spread the butter onto one side of each bread.
Place a slice of bread butter-side down. Add the grated cheese on top, then place the second slice of bread on top, butter-side up.
Cover the pan and cook for 2-3 minutes until the bottom is golden brown. Flip, and cook for another 2 minutes until crispy and the cheese is melted. Enjoy!