Butter sour dough slices. Top with cheeses. Pan grill until cheese has melted.
Oven method...
Preheat the oven to 350 degrees. Pan grill the buttered bread slices in an oven-proof skillet on the stovetop until golden. Top with cheeses. Place in oven and immediately turn off heat. Leave in oven for 10 minutes. Cheese will be melted.