In the work bowl of a food processor, fitted with the metal blade, add the flour, cake flour and baking powder. Combine the ingredients, by pulsing the ingredients 5 or 6 times. Add the butter, and again, pulse the ingredients 5 or 6 times, and then for 3-5 seconds, until there are small lumps of butter throughout the flour, about the size of peas.
Through the feed-tube, with the machine running, quickly add 1/3 cup (a little more than 5 tablespoons) ice water. After about 20-30 seconds, the dough should come together and form a ball on top of the blade. If not, add a tablespoon of water. Do not over-process to ensure a flaky crust.
Put the dough, and any little scraps on the bottom into a bowl together - pressing into two balls. Press each ball into a disc, about 1/3 to 1/2-inch thick. At this point, you can put the disc on a plate, cover with plastic wrap and refrigerate for at least 2 hours, or up to 2 days. The dough, wrapped well, also freezes well for 30-45 days (defrost in the refrigerator overnight before using).
When ready to use, dust each side of the dough with a little flour, then roll the dough on a lightly floured surface to a circle about 1/8-inch thick. Rotating the disc, as you roll to maintain an even circle.
Transfer the dough to a deep-dish 9-inch or 10-inch pie plate. Press the dough lightly into place along bottom and sides. Using a knife, trim the dough, leaving a 1-inch overlap*. Fold the dough in half to create a double thickness along the rim of the pie plate. Push lightly along the outer edge, leaving room for the dough to shrink on the rim during baking. Pinch the dough along the rim to create a decorative edge. Because this is an all-butter crust, it must be very cold going into the oven. Refrigerate the prepared shell for 30-60 minutes, or overnight lightly covered with plastic wrap.
If a recipe calls for a baked pie crust (blind bake), simply "dock" the crust, which means, using a fork, prick the crust along the bottom and sides, or use pie weights. Refrigerate for at least 30 minutes. Bake the crust at 425 degrees 15 to 18 minutes or until the sides begin to brown. (The initial high heat will force much of the steam out, helping the crust become flaky.) Remove the pan from the oven. Gently remove your pie weights. Reduce oven to 375 degrees and continue to bake the crust for several minutes until it's golden. Without the weight of a filling, a baking crust can shrink, fill with air pockets, and puff up with bubbles, so it is important to either dock the crust or weigh the crust down as it bakes. Weights are easier and you won't risk the filling leaking through the holes. This is done by lining the dough with parchment paper or foil (if you use foil, you may need to grease the dough first, to prevent the foil from sticking) and filling it with pie weights or a pie chain (or dried beans, pennies, rice, marbles, etc.) to hold its shape during baking.