In a large pot, cover the chicken with water, and bring to a full boil. Reduce heat, add chicken bouillon cubes and onion, and continue cooking chicken at a low boil until chicken is done, but not quite falling off the bone, approximately 30 minutes. Turn off the heat; remove the chicken from broth and remove skin and bones. Cut up and return to the broth-heat still off. Mix flour, salt, and mace in a large bowl. Crumble the butter into the flour with a fork, and add the eggs and milk. Mix with a strong wooden spoon until the dough is smooth. Divide dough into four portions to make it easy to work with. On a well-floured surface, roll the dough to a 1/4-inch thickness. Put the broth back on the heat and bring to a rolling boil. Cut the rolled-out dough into 2 to 3-inch squares and drop them into the boiling broth. Stir occasionally to keep the dough from sticking together as it boils. After all the dough has been dropped in the pot, turn the heat down to low, and simmer the "pop-eye", lid on, for about 20 minutes. When it becomes irresistibly creamy and thick.
Recipe courtesy of Margie Lapanja, author of Goddess in the Kitchen