Duchesse Potatoes

3 cups potatoes, peeled
2/3 cup butter
4 egg yolks
salt
water

1. Boil the potatoes in plenty of salted water until very tender, about 45 minutes.
2. Preheat the oven to 400 degrees.
3. Drain and peel the potatoes, mash and mix with butter and salt, then all but 1 egg yolk.
4. Pipe through piping bag or form into smoothly circles onto a greased baking sheet.
5. Brush tops with remaining egg yolk and bake until browned, about 10 minutes.

Makes 6 servings