Place flours, buttermilk powder, salt, sugar, baking powder and baking soda in a large bowl. Use a wire whisk to combine dry ingredients, then cut in the shortening and butter with butter knives or a pastry blender, to form a coarse, crumbly mixture. Store mixture in double zip bags in the freezer for up to three months.

To make biscuits:

3 cups Biscuit Mix
3/4 - 1 cup ice water

Preheat oven to 425 degrees F. Place three cups of biscuit mix in a medium sized bowl. Make a 'well' in the center and stir in almost all of the
ice water or as needed. Gently knead on a lightly floured beard about 8 times. Do not overwork dough. Roll or pat out to a thickness of 1/2 inch. Cut into rounds between 2 and 2 1/2 inches across, making certain not to twist the biscuit cutter around as you cut the biscuits. Place on ungreased cookie sheet and bake until
light golden brown, about 10-12 minutes. Serve hot. These can also be patted into an 8 inch square baking pan or a 9 inch cast iron. Bake
until golden, then cut into squares.

To give as a gift, place a 6 - 8 ounce jar on top of a folded paper towel in the bottom of a wide mouth quart jar. Cover this with 3 cups of biscuit
mix and seal the jar. Decorate the jar as desired, and attach the instructions for baking which are above. Be sure to mention that this should be refrigerated until it is used, but not frozen, as the jar may break.

Contributor's note: Biscuit Mix can also be combined usine a large food processor. Process in two half batches, pulsing the processor to cut the fat into the flour.