For a pre-baked pie crust, preheat your oven to 375° F. Place the flours, flaxseed meal, and salt in a food processor and pulse to combine.
Add the butter in tablespoon size chunks, and pulse until the flour mixture looks crumbly. This will take a few repetitions of pulsing.
Add the egg and pulse until the dough forms a ball, it may take quite a few pulses but evntually the dough will form a ball. Cut two pieces of wax paper and lightly dust one piece with tapioca flour.
Place the dough ball on the dusted wax paper and place the other piece of wax paper on top of the ball. Use a rolling pin and roll the dough out into a circle that is about 1/8 of an inch thick.
Peel the top layer of wax paper off the dough and flip the dough into a lightly buttered 9" pie plate. Peel off the other piece of wax paper and press the dough into the shape of the pie plate.
Trim away extra dough from the edges, then crimp the edges with your fingers. Prick the bottom of the crust thoroughly with a fork. For a pre-baked crust, bake for 18-20 minutes.
Note: I have skipped rolling out the dough and have simply patted the dough into the pie plate. Both versions turn out fine!