Beat softened butter with a hand mixer in a large bowl until frothy. Add the egg and mix well. Stir in the semolina, season with salt, and grate in nutmeg to taste. Stir to combine. Let dough rest for approx. 60 min. at room temperature.
Bring the beef stock to a boil in a pot. Shape the dumplings using two hot, wet teaspoons, and add them to the boiling stock. Let the dumplings cook for approx. 15 min. and then lift them out gently with a slotted spoon. Serve with the stock. Enjoy!