Really anything you want in your sandwich (cheese with some kind of meat works well)
1/ Make sanswich in the normal way.
2/Heat up oil in a frying pan.
3/Fry your sandwich on both sides until golden brown.
If your stuck for ideas heare are a few
Cheese and ham
Cheese and Onion
Cheese and Marmite
(you get the idea any sandwich you can think of)
If you fancy something sweet:
Chocolate spread and marshmallow
Bana and brown sugar