Make the crust. Using a food processor is the fastest method. To the processor, add all purpose flour, salt, sugar, shortening and cold butter cut into small cubes. Pulse about 8 times until you get a crumbly mixture. You should see pieces of butter. Add ice cold water a little bit at a time and pulse until just before the dough forms into a ball. It happens very fast. It should hold together nicely. Take the blade out first. Then put the dough onto plastic wrap. Place the wrap over the dough and form into a disc. Wrap well. You should see pieces of butter throughout the dough. Put this is in the refrigerator for at least one hour. The dough can be made ahead and frozen for a few months or refrigerated for 3 days.