Egg banjo

Egg banjo is a British sandwich that was especially popular with British troops during WWII. The sandwich usually consists of nearly stale white bread that's sliced, spread with butter, filled with fried eggs, and enriched with brown sauce or ketchup.

The yolk and the sauce often dribble down one's chest, so the hand is moved to wipe it, while the other hand is still holding the sandwich, so it looks like one's playing an air banjo, hence the name egg banjo. The sandwich is still popular in Commonwealth countries such as Malaysia.