Patate Duchessa al Parmigiano (Italian Duchess Potatoes) Patate duchessa are piped potato rosettes, baked until the ridges colour and the inside stays light. They are one of the few Italian side dishes that entered the kitchen from the dining rooms of the aristocracy rather than from the fields. The mixture is nothing more than dry floury potato, egg yolk, butter and Parmigiano Reggiano, which is exactly why every one of those four has to be right. Everything that can go wron