Duchess potatoes

Duchess potatoes (French: pommes de terre duchesse) consist of a purée of mashed potato, egg yolk, and butter, which is forced from a piping bag or hand-moulded into various shapes which are then baked in a high temperature oven until golden. They are typically seasoned similarly to mashed potatoes with, for example, salt, pepper, and nutmeg. They are a classic item of French cuisine, and are found in historic French cookbooks.