Spread softened butter on each side of the sandwich bread.
Heat a skillet over medium heat, then place 2 slices of bread in the skillet. Place the cheese on one slice and top with basil leaves. Then, top with the second slice of bread.
Cook the sandwich for 2–3 minutes per side or until golden brown and the cheese is melted. Repeat with the remaining ingredients.
Remove the sandwiches from the skillet. Place them on a cutting board, and slice them in half. Serve warm!