Prepare crust: In medium bowl, combine flour, baking powder and 1/4 cup sugar.
With pastry blender or 2 knives used scissors fashion, cut in butter until mixture resembles fine crumbs.
Add 1/2 cup cream and stir with fork until dough comes together. Gather dough into a ball and place on lightly floured sheet of waxed paper. With floured rolling pin, roll dough to a 9-inch round.
Slide waxed paper onto cookie sheet and refrigerate dough until ready to use.
In cup, mix cinnamon and remaining sugar.
Prepare fruit filling: Preheat oven to 400 degrees F. Place cookie sheet lined with foil in oven. In 4-quart saucepan, stir sugar, water and cornstarch until cornstarch dissolves; stir in peaches.
Heat to boiling over medium-high heat, stirring often. Reduce heat to low; simmer 2 minutes, stirring often. Remove from heat; gently stir in berries. Pour filling into 9-inch deep dish pie plate.
Immediately, while filling is hot, remove dough round from refrigerator and, using waxed paper, invert dough over fruit mixture. Peef off paper. Cut 4-inch X in center of round, fold back points to make square opening.
Brush dough with remaining cream; sprinkle with cinnamon sugar.
Bake pie on foil-lined cookie sheet 35-40 minutes or until fruit is bubbly in center. If crust is browning too quickly, loosely cover pie with foil after 25 minutes. Cool pie on wire rack.