Step 1:
In a food processor, combine flours, salt and sugar. Pulse 5 times to combine. Add shortening and process until the mixture resembles wet sand. Scatter butter into the food processor and run again for about 10 seconds, or until the butter is in tiny pieces, none larger than a small pea. Sprinkle about 4 tablespoons of ice water into the food processor and pulse until the dough barely begins to come together. Add more water, if needed. Turn dough onto a clean work surface and quickly press into two equal pieces. Shape into disks, wrap in plastic, and refrigerate dough for 1 hour.