1 ¼ cup flour
1 ½ teaspoons sugar
½ teaspoon salt
1 stick butter, cut into small (1/2-inch) cubes, chilled
¼ cup of ice water (maybe more)
1 cup blueberries
1 cup raspberries
¼ cup sugar
1 egg, beaten
1 tablespoon butter, melted
1. Preheat oven to 425F.
2. Make the crust dough. In a food processor, pulse the flour, 1 ½ teaspoons sugar, and salt, until well mixed. Add the cubed butter, and pulse 8 times. The butter should still be the size of peas in the mixture. Slowly add the ice water, a tablespoon or two at a time, pulsing after each addition, until the dough just begins to clump.
3. Turn out onto a clean surface. Use your hands to form into a disc. Do not over-knead. Sprinkle with a little flour on all sides, wrap with plastic, and place into the refrigerator to chill for at least 30 minutes.
4. Toss berries with sugar and refrigerate.
5. Whisk egg in small bowl and set aside.
6. On a lightly floured, clean, smooth surface, roll out the dough to about a 12-inch diameter. Gently lift up the rolled out dough and place it on a rimmed baking sheet.
7. Arrange berries a single layer in the center of the dough, forming about a 7 or 8-inch circle. Dot with a little butter. Fold the outer edges of the dough round over the filling, by about 2-inches all the way around, use a pastry brush to coat the dough with an egg wash.
8. Place in the oven and cook for about 15-20 minutes, until nicely browned. Remove from the oven and let cool on the baking sheet, over a rack, about 15 minutes.