Place a cast iron skillet on a burner. (Don't turn on just yet)
Slice the cheese on a cutting board.
Take one slice of bread and spread with 2 tsp butter.
Place butter side down in the skillet.
Top with the cheese.
Spread 2 tsp butter on the other slice and top the sandwich, butter side up.
Turn the burner on 3-4 or medium-low heat.
Cook for 4-5 minutes or until golden brown.
Carefully flip the sandwich and continue to bake for 2-3 minutes.
Notes
You can use any combination of cheeses you prefer for a customizable sandwich.Store any leftover sandwich in an airtight container in the fridge and reheat in a toaster oven or under the broiler.