Preheat a panini grill, skillet or grill pan on medium heat.
Spread a thin layer of butter on one side of each slice of bread. Place the Red Leicester on a slice of bread, with the buttered side facing down. Close the sandwich with the buttered sides facing out.
Place the sandwiches on the grill and cook on both sides until golden brown and the cheese is melted, about 3-4 minutes on each side (or about 4 minutes in a panini grill).