What is the meaning of Custard_pie?

A pie made from an uncooked custard mixture added to an uncooked or partially cooked crust and then baked as a whole.

A prop used in slapstick, consisting of an open pie filled with custard or cream (or, more often nowadays, simply a paper plate covered with shaving foam or a similar substance) that is pushed into another person's face.

Source: wiktionary.org