To Make the Crust:

1. In the bowl of a food processor, pulse flours and sugar just to combine. Add pieces of butter and pulse about 5 times to cut in the butter. Add water and pulse again, about 8 to 10 times. Do not over mix. The dough should feel dry when you run your fingers through it, but hold together in a ball when you squeeze it in your hand.
2. Spread a large piece of plastic wrap (about 1 1/2 feet long) on the counter. Gently dump the dough (it will be crumbly) onto plastic wrap. Pull plastic wrap together around the dough and mold it into a disc, twisting the top of the plastic wrap to seal. Refrigerate for at least 30 minutes, and up to 2 days.
3. On a lightly floured surface, use a rolling pin to roll the dough into a circle, about 12 inches (30 cm) in diameter. Fold the dough in half and gently lift it onto a parchment-lined baking sheet. Unfold dough so it lies flat. Cover and refrigerate until ready to use.

To Assemble the Tart:

1. Heat oven to 375 F (190 C). Remove dough from refrigerator.
2. In a medium bowl, gently toss peaches with powdered sugar and almond extract. Mound peaches and blackberries in center of dough, leaving a 2 inch border of dough around the fruit. Fold dough over outer edge of fruit, pleating every 2 to 3 inches.
3. Whisk egg and water. Pour egg wash through a strainer to remove stringy bits. Brush dough with strained egg wash and sprinkle with raw sugar. Bake until crust is golden brown and fruit is bubbling, about 40 to 50 minutes.
4. Let tart cool until filling thickens, about 30 minutes. Using parchment, slide tart onto serving board. Tear parchment on one edge, then pull and tear parchment away from the tart until it slides out from underneath. Serve warm or at room temp.