HEAT a griddle on med-low. Spread butter on one side of each of the 4 slices of bread.
PLACE bread butter side down on the griddle. Top two slices of bread with cheese, basil, and tomatoes. Top these slices of bread with the other two slices to make a sandwich.
HEAT until bread is golden brown, then flip. Heat until the other side is golden brown and cheese is melted, then remove from griddle. Serve and enjoy.