Potato cake

A restaurant dish if there ever was one, and it crops up in various guises, usually placed under an expensive piece of meat. If the cake is assembled with butter it could be Pommes Darphin or more commonly Pommes Anna; if cooked in rendered foie gras fat it becomes Pommes Sarladaise; the inclusion of onions would make it a Gâteau de pommes de terre Lyonnaise; and to grate the potato then bake it in butter would transport us from France to Switzerland, and we would be making Rösti. This vers