This is a bit of a cheat recipe, since it's ridiculously simple and really just a snack. Makes for great late-night eating if you get the munchies.
Mature cheddar cheese
1 small onion
Pre-heat oven to 200 degrees centigrade. Butter 8 slices of toast. Slice cheese. Chop onion into small pieces.
Place sliced cheese onto bread, then add onion pieces on top of the cheese. Lightly dust with paprika.
Cook in oven until the cheese has melted, and serve.