2 1/4 cups all-purpose flour
1 cup cake flour
1 1/2 teaspoons grated lemon peel
1/2 teaspoon salt
1/4 teaspoon baking powder
6 tablespoons ice water more or less
1 tablespoon apple cider vinegar
Nonstick vegetable oil spray
3/4 cup sugar
1/4 cup cornstarch
3 cups fresh raspberries
3 cups fresh blackberries
Additional sugar (optional)
For Crust: Combine first 5 ingredients in processor; blend 5 seconds. Add butter and blend, using on/off turns, until mixture resembles coarse meal. Add 5 tablespoons water and vinegar. Using on/off turns, blend until moist clumps form, adding more water if dough is dry. Gather dough into ball; divide in half. Shape each half into disk. Wrap in plastic and chill at least 1 hour and up to 1 day.
Roll out 1 dough disk on lightly floured surface to 12-inch round; transfer to prepared pie dish. Spoon filling into dough-lined dish. Roll out second dough disk to 13-inch round. Drape dough over filling, and trim overhang to 1/2 inch. Press edges together to seal; fold overhang under and crimp decoratively. Cut several small slashes in top crust to vent. Sprinkle with additional sugar, if desired.