Using a spoon, mix 1 Tablespoon unsalted butter (softened to room temperature) with 1 medium egg in a bowl.
Combine ¾ cup all-purpose flour with ¼ teaspoon baking powder and ½ teaspoon salt. Gradually add this dry mixture and 2 Tablespoons milk to the creamed butter, stirring continuously.
Using a spoon or fork, combine the ingredients until they form a soft dough.
Use a knife to cut the dough into small dumplings.
Drop them into the soup and let them simmer for about 4-5 minutes. The dumplings are done when they float to the surface.
Notes
Add the dumplings only at the end of cooking the soup to prevent them from falling apart.
The exact amount of flour needed depends on the size of the egg and the amount of butter and milk. Gradually add the flour in small amounts towards the end. Finally, knead the dough for about a minute on a floured work surface.
Test-cook one dumpling first. If it falls apart, knead a bit more flour into the dough.