Preheat. Preheat oven to 400ºF.
Prep the bread: Spread the softened butter on one side (outside/top) of the sliced bread.
Assemble: Lay bread out in a single layer on a baking sheet, with buttered side down. Top with cheese, then close the sandwich with another slice of bread. Then butter the top of the second slice of bread.
Bake: Bake the sandwiches for 4 minutes, flip them over, then bake for another 2-4 minutes or until both sides are golden-brown and the cheese is melty!