In a large mixing bowl combine the flour, baking powder and salt. Using a cheese grater, grate the cold butter into the flour mixture and stir to coat the butter.
Pour in the milk and stir until a ball forms with the dough. You can knead it a few times in the bowl if needed.
Pull off one inch pieces of the dough and drop into the soup. Cover with a lid and allow to simmer for 15-20 minutes, until the dumplings are floating at the top of the soup.
To thicken the soup, combine the cornstarch and cold water and pour into the soup. Stir continually until thickened
