Boil the potatoes and peel them. Then mash them. Add the butter and stir well.
Next, add the eggs and spices to taste. Pour in the milk. Stir well.
Grate the feta cheese coarsely, add it at the end. Stir again until homogeneous.
Next, transfer the potato mixture to a pastry bag with a large tip. Spray it out onto baking paper.
Bake them in a preheated 392°F (200 °C) oven. The Duchess Potatoes need to redden slightly.