2 1/2 c. unbleached all purpose flour
1 t. salt
2 T. sugar
1 1/2 sticks cold unsalted butter cut into 1/4 inch slices
1/2 c. cold vegetable shortening, cut into 4 pieces
1/4 c. white vinegar
1/4 c. cold water
Process 1 1/2 c. flour, salt & sugar in food processor until combined, about 2 one-second pulses. Add butter & shortening & process until homogeneous dough just starts to collect in uneven clumps, about 15 seconds (dough will resemble cottage cheese curds & there should be no uncoated flour). Scrape bowl with rubber spatula & redistribute dough evenly around processor blade. Add remaining cup flour & pulse until mixture is evenly distributed around bowl & mass of dough has been broken up, 4-6 quick pulses. Empty into medium bowl.
Sprinkle vinegar & water over mixture. With rubber spatula, use folding motion to mix, pressing down on dough until dough is slightly tacky & sticks together. Divide dough into two even balls & flatten each into 4-inch disk. Wrap each in plastic wrap & refrigerate at least 45 minutes or up to 2 days.
Source Recipe: http://triedandtruefavoriterecipes.blogspot.com