Dice the butter and shortening and return to the refrigerator (I put mine in the freezer.) while you prepare the flour mixture.
Add the dry ingredients to the bowl of a food processor and pulse a few times to blend.
Add the butter and shortening and pulse 8 - 12 times, until butter is the size of peas.
While the machine is running, slowly pour water down the feed tube. Stop the machine.
Pulse the machine until the dough begins to form a ball.
Dump out on a floured surface, roll into a ball and divide into halves.
Wrap each half in plastic wrap or parchment paper and refrigerate for at least 30 minutes.
When ready, roll each disk out onto a well-floured surface. Roll from center to edge to form a circle. Turn and flour the dough as you roll to keep it from sticking to the surface. Place in a pie plate. Repeat for top crust or for a second single crust.