1.Preheat oven to 180°C. Oil and line oven trays with baking paper.
2.Boil, steam or microwave potato until tender; drain. Mash potato in large bowl with egg yolks and butter.
3.Spoon potato mixture into large piping bag fitted with a 1cm (½-inch) fluted tube; pipe potato into 3cm (1-inch) rosette-shaped swirls onto oven trays.
4.Bake in oven about 30 minutes or until browned lightly.
For a variation, stir ½ cup finely grated parmesan cheese into the potato mixture before piping. The potato can be piped up to 3 hours ahead; keep, covered, in the refrigerator. Coliban, nicola or lasoda potatoes are suitable for this recipe.Note