Wash hands with warm, soapy water for 20 seconds.
In a large bowl combine flours, baking powder, sugar, and salt.
Drizzle oil over dry mixture. Cut in with pastry blender, fork, or fingers until it resembles coarse cornmeal.
Store in a tightly covered container in refrigerator. Keeps 3 months in refrigerator.
To measure for recipes, first stir the mixture. Then, gently spoon mixture into a measuring cup, and level.