Boil the quail eggs for 3 minutes, let them cool in ice water and peel them.
Wash the potatoes and cook them in salted water with their skins on. Peel the potatoes while they are hot and let them evaporate in the oven in a baking dish at 120 ° C for approx. 10-15 minutes.
Then press the hot potatoes into a bowl with the potato press. Add the melted butter, cornstarch, egg yolk, 1 teaspoon salt and nutmeg as desired and knead quickly to form a smooth dough.
Place a large saucepan with water and bring to a boil.
Shape the dumpling into 4 dumplings and fill each with 2 quail eggs. Carefully add to the boiling salted water. Reduce the heat and let the dumplings soak in the hot water for about 12-15 minutes.
Heat 0.5 liters of creamy mushroom sauce.
As soon as the dumplings float on the surface, they are ready and can be lifted out with a skimmer. Arrange the dumplings with the creamy mushroom sauce and serve.