Prepare a pre-dough from approx. 50 g flour, sugar and the dry yeast.
Let it rise in a warm place. Mix the remaining flour with 1 pinch of salt and the egg. Warm the milk. Add the pre-dough to the flour, stir it in and gradually add the milk. The dough should not stick, if necessary help with a little flour.
Let the dough rise in a warm place until it has about doubled in volume.
Peel and cook the potatoes. Cut the sausage and onions into cubes and fry them vigorously in a pan. Finely mash the potatoes with 1 tablespoon butter and milk (blender), the consistency of the soup is a matter of taste, can be controlled by adding milk. Season to taste with salt, pepper, vegetable stock and nutmeg. Add the sausage and onions and allow to stand.
Form the dough into small balls. Let rise again. In a pan, heat 50 g butter with 1 cup water and 1/2 teaspoon salt. Add the dough balls and put the lid on the pan. After the typical hissing of the steamed noodles, let them toast a little (slightly brownish color in the pan). Remove the lid quickly so that no water drips onto the steamed noodles. Serve the steamed noodles with the potato soup. The soup can be refined with a little parsley.
