Preheat oven to 400F degrees. Line large baking sheet with parchment paper and set aside.
Melt butter in nonstick skillet over medium heat. Add apple slices and saute five minutes to brown slightly. Stir in brown sugar, raspberries and cinnamon. Reduce heat to medium-low and cook two minutes until sugar is dissolved. Stir in cornstarch mixture and cook one minute. Remove from heat.
Unfold pastry and cut in half lengthwise, parallel to fold. On floured surface, roll out one pastry half to 12x5 inch rectangle. Transfer to baking sheet. Spoon apple mixture over pastry, leaving one inch border at edges. Brush edges with egg white. Roll out second half of pastry to 12.5x6-inch rectangle. Fold pastry in half lengthwise and then cut slits in dough, but not all the way to edges. Transfer on top of filling, then unfold. Seal at edges.
Brush pastry with egg white. Sprinkle with raw sugar. Bake for 18 to 20 minutes. Cool before serving.