Thaw puff pastry according to the package instructions.
Line 2 baking sheets with parchment paper. Preheat oven to 400 Fahrenheit.
Wash the berries. Hull the strawberries and slice them into ¼ inch thick slices. Cut the strawberries vertically, horizontally or in both directions.
On a lightly floured surface, roll out each sheet of puff pastry to roughly a 10 by 12 inch rectangle. Use a small knife to cut out 5 4-inch circles* from each sheet of puff pastry. Use a fork to poke holes in the middle of the circles. Place five of them on each baking sheet.
In a medium bowl, stir to combine the cornstarch and granulated sugar. Add the strawberries, blueberries and the almond (or vanilla) extract. Toss gently til the berries are coated evenly.
Spoon about a rounded tablespoon of the fruit in the middle. (Try not to scoop up any fruit juice if there is any in the bowl and to top the pies with the berries only). Leave a 1/2 inch border on the edges. It's okay if the fruit is piled up a bit. Try to divide the berries evenly among the pies.
In a small bowl, make the egg wash by whisking together the egg and water. Brush the edges with egg wash. Sprinkle generously with turbinado sugar.
Bake 12-14 minutes until the crust is golden brown. Allow to cool on baking sheet for about 15 minutes then enjoy!