Place a pan on medium heat and allow it to preheat for 1 to 2 minutes so it is evenly warm.
Spread butter evenly on one side of each bread slice, making sure to reach all edges.
Place one slice of bread in the pan with the buttered side facing down and let it begin to toast.
Add cheese slices on top of the bread, covering as much surface as possible for even melting.
Place the second slice of bread on top with the buttered side facing up and press gently.
Cook the sandwich for 2 to 3 minutes until the bottom turns golden brown and crisp.
Carefully flip the sandwich using a spatula and cook the other side for another 2 to 3 minutes.
Continue cooking until both sides are golden and the cheese inside is fully melted.
Remove from the pan and let it rest briefly before slicing.
Slice and serve warm for the best taste and texture.