Boil the potatoes in salted water until tender. Once slightly cooled, peel and press them through a potato ricer.
When the potatoes are lukewarm, add the liquid butter, egg, nutmeg, and potato starch. Knead the mixture on a surface dusted with potato starch until it forms a smooth dough. Depending on the potatoes, you may need to adjust the amount of potato starch, but be cautious not to add too much, as it could affect the dumplings' texture.
Chill the potato dough for 1 day (optional). You can also quickly chill for 20 minutes in the freezer.
On the following day, shape the dumplings into the desired size, lightly dusting them with potato starch to prevent sticking. If not cooking immediately, refrigerate the dumplings.
Bring a large pot of salted water to a simmer, then reduce the heat (avoid boiling the dumplings). Carefully slide the dumplings into the water, allowing them to cook without overcrowding the pot. If not cooking all at once, keep the dumplings refrigerated.
Once the dumplings float to the water's surface (which may take about 8-10 minutes), let them simmer gently for an additional 15 minutes.
Enjoy these German Potato Dumplings as a delightful accompaniment to your favorite hearty dishes. The perfect blend of tradition and flavor awaits!