1/4 c. plus 2 tbsp. sour cream
2 tbsp. ice water
1 tsp. sugar
3/4 tsp. salt
2 1/4 c. all purpose flour
1/4 c. cake flour
1/2 c. (1 stick) chilled unsalted butter
1/2 c. chilled solid vegetable shortening

Combine sour cream, water, sugar and salt in small bowl. Combine both flours in large bowl. Cut in butter and shortening with fingers or pastry blender until mixture resembles coarse meal. Add sour cream mixture and stir just until dough forms. Turn dough out onto lightly floured work surface. Divide in half. Form each half into ball; flatten into disk. Wrap each disk in plastic. Refrigerate 1 hour, (can be prepared 1 month ahead; freeze).