Vanilla-Scented Nectarine and Blackberry Pie

FOR THE FILLING:
Line baking sheet with foil; place in bottom of oven (to catch any potential spills). Position rack in center of oven and preheat to 375 degrees F.

Whisk 3/4 cup sugar, brown sugar, cornstarch and cinnamon in large bowl to blend well. Add nectarines and blackberries. Using small knife, scrape in seeds from vanilla bean; discard bean. Toss gently to blend well. Let stand until juices form, about 15 minutes.

TO ASSEMBLE:
Roll out 1 pie crust disk on generously floured surface to 13-inch round. Transfer to 10-inch-diameter glass pie dish. Spoon filling into crust. Roll our second pie crust disk on floured surface to 13-inch round. Drape crust over filling. Press top and bottom crusts together to seal. Fold edges under and crimp decoratively, forming high standing rim 1/2 to- 3/4-inch above sides of dish. Cut four 2-inch long slits in center of top crust to allow steam to escape during baking. Brush top of crust (not edges) lightly with whipped cream. Sprinkle top of pie with remaining 1 tablespoon sugar.

Bake pie 30 minutes. Cover edges with foil collar to protect from overbrowning. Continue to bake pie until crust is golden brown and juices bubble thickly through slits, about 1 hour longer. Transfer to rack and cool at least 3 hours. Cut pie into wedges. Serve with vanilla Ice cream or sweetened whipped cream, if desired.