1. Butter bread slices on 1 side. Turn them over. Lay 2 cheese slices on 1 bread slice. Top with the other bread slice, buttered side up.
2. Heat a medium frying pan over medium heat. Flick a drop of water into the pan; if it sizzles and evaporates, the pan is hot enough.
3. Put sandwich, buttered side down, in pan. Let it cook 3 to 4 minutes, or until golden and crunchy underneath. Turn and let cook another 3 to 4 minutes, or until golden and crunchy.
Choose a cheese that melts well, such as cheddar, jack, Colby, gruyère, Swiss, fontina, provolone, or brie.
But why stop there?