In a large sifter, combine flour, sugar, cornstarch, baking powder
and salt. Sift, in batches, into a large bowl. Use a pastry blender
or a heavy duty mixer to blend in the shortening until the mixture
resembles cornmeal in texture. Spoon into a container with a 20-cup
capacity and a tight fitting lid. Seal container; label with date
and contents. Store in a cool, dry place. Use within 10-12 weeks.
