Dice Butter and return to the fridge- butter needs to be cold. Place Flour, sugar and salt into food processor and pulse 3 times. Add the shortening and butter to this mixture. Pulse again about 15 times, or until the mix is crumbly.
While the processor is running on pulse, add ice water a little at a time, until the dough begins to form a ball.
Once you have a ball, remove from processor onto a lightly floured surface and cut in half. This is enough for two pie crusts, or 24 pie tarts.