Duchess Potatoes

America's Test Kitchens uses 1/2 tsp baking powder per 3 pounds of potatoes (around 9 medium potatoes) to give their potatoes an airier texture.

6 medium baking potatoes, peeled and boiled
1/4 cup milk
1/4 cup butter (1/2 stick)
salt & pepper
1 egg, beaten
extra melted butter

Beat the potatoes, milk, butter, and salt & pepper together until fluffy. Add the egg and mix well.

Drop on ungreased baking sheets, or form rosettes by piping through a decorator's tube. Brush lightly with melted butter.

Bake at 425° for 15 minutes until lightly browned.

MAKE AHEAD Once piped onto the baking sheet, the potatoes can be covered loosely with plastic wrap and refrigerated for 24 hours.