Sift together flour, Clabber Girl Baking Powder and salt, cut in shortening. Stir in milk; mix until soft dough is formed. Knead 4 strokes, roll to 1/8" thickness. Cut into 6 squares. Core and peel apples, placing one on each square. Combine sugar and cinnamon, sprinkle into center of each apple, adding 1/2 teaspoon margarine to each. Moisten edges of dough; press corners up over apples and brush with milk.
Place in greased baking pan and bake at 350 for 30 minutes.
Heat water, vinegar and butter. Combine remaining ingredients; mix thoroughly. Stir into hot mixture; cook over low heat, stirring constantly until thickened.
Pour sauce over hot apple dumplings.
Makes 6 servings.