In the bowl of a food processor, combine the sugar, both flours, milk powder, baking powder and salt. Process for 15 seconds. Add the pieces of butter and lightly toss with a fork so they are coated with the flour mixture. Sprinkle the vanilla over the top. Pulse until the mixture is fine and crumbly, about 10 one-second pulses. Use immediately or store in an airtight bag or container in the freezer for up to 2 months.
Notes
Note: For instructions on how to make an actual cake with this mix, please visit Mel's Kitchen Cafe.Nutritional values are based on one cup of mix