Peel the potatoes, wash them and boil them in salted water. Mash them with a few spoonfuls of the broth, add the butter and stir. The mashed potatoes need to be a bit thick.
Chop the onion and parsley finely. Mix the mince with all of the ingredients and leave it to sit for an hour. Form round meatballs and place them in greased muffin forms.
Make a small indentation with your finger in the meatballs and pour the mashed potatoes in it.
Bake in a preheated 392°F (200 °C) oven for about 15 min. Serve with your favorite salad.