Step 1: Prepare chicken stew by combining stew ingredients (except milk) in a large stock pot and simmering at least 45 minutes, until chicken falls off the bone. The longer you simmer, the richer the flavor will be. If using a whole chicken, remove the bones from the broth and set broth aside, or keep warm on low while preparing dumplings. Step 2: In a large mixing or food processor bowl, combine dry ingredients and mix thoroughly. Cut margarine, butter or shortening into dry ingredients until mixture resembles coarse cornmeal. Add buttermilk and and beat until mixture forms a ball (a mixer or food processor works well). Cover dough with plastic wrap and allow to rest for 30 minutes. Lightly flour your rolling surface with tapioca flour, and dust dough with additional tapioca flour as you roll the dough to a 1/4 inch thickness. A flexible cutting board works well for this purpose. Cut the dough into strips about 1 inch wide and 2 inches long. Bring the soup back to a boil, and slide dumplings into the boiling soup. Cover and boil for 20 minutes. Don't peek or the dumplings will be tough! Remove from heat and stir in the 1 cup of milk.