Basic Cookie Mix

Combine flour, granulated sugar, brown sugar, baking powder, and salt in a
large bowl. (You can use an electric mixer on slow speed for mixing.) Add
shortening and butter; cut in with pastry blender or hands until mixture
resembles coarse cornmeal. Store in an airtight container in refrigerator.

NOTE: After refrigeration, measure amount of mix needed; bring to room
temperature for easier blending.