Absolutely delicious! The combination of raspberry/blueberry was perfect!.

2 1/2 cups all-purpose flour
Pinch of salt
1/2 cup chilled unsalted butter, cut into 1/2-inch cubes
6 tablespoons chilled solid vegetable shortening, cut into 1/2-inch cubes
1/4 cup sour cream or plain yogurt
3 tablespoons ice water

Nonstick vegetable oil spray for the pie plate

3 cups fresh raspberries
3 cups fresh blueberries
1 cup sugar
1/3 cup tapioca or corn starch
juice of half a lemon

1 large egg
2 tablespoons milk
2 tablespoons raw sugar*
Vanilla ice cream is a must 🙂
preparation

Add flour and salt in your food processor bowl. Add butter and shortening and give it a few on off turns until pea-size pieces form. Add sour cream and 3 tablespoons ice water. Buzz this until dough comes together. Gather dough into ball and divide into 2 pieces. Flatten each into disk. Wrap dough in plastic and refrigerate 2 hours. (Can be made 1 day ahead. Keep refrigerated. Let dough soften slightly at room temperature before continuing.)

Preheat oven to 375°F. Spray 9-inch-diameter glass pie dish with nonstick spray. Roll out 1 dough disk on lightly floured surface to 12- to 13-inch round. Line prepared pie dish with dough. Roll out remaining disk on lightly floured surface to 12- to 13-inch round.

Mix raspberries, blueberries, 1 cup sugar, tapioca, and lemon juice in large bowl. Spoon berry mixture into crust-lined pie dish. Top with second crust, trimming excess dough. Crimp edges together. Cut 3/4-inch hole in center of top crust.

Whisk egg and milk in small bowl to blend. Brush some of mixture over crust. Sprinkle with raw sugar. Bake pie 15 minutes; reduce heat to 350°F. Continue baking until crust browns and juices bubble thickly (cover crust with foil after 30 minutes to prevent overbrowning), about 1 hour.

Cool about 2 hours. (Pie can be made 6 hours ahead. Let stand at room temperature.) Cut pie into wedges and serve warm or at room temperature with ice cream.

*Also called turbinado or demerara sugar; available at natural foods stores and most supermarkets.