Sift dry ingredients together in a large bowl. With two knives, a pastry blender, or food processor, add the shortening in spoonfuls and cut it in until the mixture is the texture of coarse cornmeal.
If you are using a food processor, pulse it and watch closely. Keep mix stored in a tightly closed container. It will keep on the shelf for 1 to 6 months in dry weather. In very hot and humid weather, keep the mix in the refrigerator.Servings: 12 cups