1. Stir together flour and salt in a large bowl. Cut butter into flour mixture with a pastry blender until mixture resembles small peas. Stir in cheese. Drizzle 1/2 cup ice water over flour mixture, stirring with a fork until dry ingredients are moistened and dough is crumbly but forms a ball when pressed together, adding more ice water, 1 Tbsp. at a time, if necessary (up to 1/4 cup). Divide dough in half. Place each half on a large piece of plastic wrap. Shape each dough half into a flat disk. Wrap each disk in plastic wrap, and chill 2 to 24 hours.
2. Preheat oven to 400°. Place 1 dough disk on a lightly floured surface; sprinkle dough lightly with flour. Roll dough to about 1/4-inch thickness. Starting at 1 edge of dough, wrap dough around rolling pin. Place rolling pin over a 9-inch pie plate, and unroll dough over pie plate. Press dough into pie plate; trim off excess crust along edges. Brush edges of crust lightly with egg; reserve remaining egg. Spoon Blackberry-Apple Pie Filling into crust, mounding filling slightly in center.
3. Roll remaining dough disk to about 1/4-inch thickness on a lightly floured surface. Cut dough into 9 (1-inch-wide) strips. Arrange strips in a lattice design over filling; gently press ends of strips into bottom crust; crimp edge of crust. Brush lattice with reserved egg; sprinkle with sparkling sugar. Place on a baking sheet.
4. Bake at 400° on lower oven rack 45 to 50 minutes. Cover loosely with foil to prevent excessive browning, and bake 25 more minutes or until juices are thick and bubbly. Cool on a wire rack 2 hours.
Try This Twist! Cranberry-Apple Pie: Substitute Cranberry-Apple Pie Filling for Blackberry-Apple Pie Filling. Prepare as directed.