- 1 1/2 cups all-purpose flour
- 1/2 cup sugar
- 1 teaspoon baking powder
- 1/4 teaspoon salt
- 1 stick (1/2 cup) cold unsalted butter, cut into 1/2-inch cubes
- 1 large egg
- 1 teaspoon vanilla
- 1/2 cup sugar
- 2 tablespoons all-purpose flour
- 1 tablespoon quick-cooking tapioca
- 2 lb firm-ripe large peaches (about 4), halved lengthwise, pitted, and each half cut lengthwise into fourths
- 1 cup blueberries (1/2 pint)
- 1 tablespoon fresh lemon juice
- Special equipment: a 9- to 91/2-inch (24-cm) springform pan; an electric coffee/spice grinder
Pulse together flour, sugar, baking powder, and salt in a food processor until combined. Add butter and pulse just until mixture resembles coarse meal with some small (roughly pea-size) butter lumps. Add egg and vanilla and pulse just until dough clumps and begins to form a ball, about 15 pulses.
Press dough onto bottom and evenly (about 1/4 inch thick) all the way up side of springform pan with floured fingertips. Chill pastry in pan until firm, about 10 minutes.
Make filling while pastry chills:
Put oven rack in middle position and preheat oven to 375°F.
Grind 2 tablespoons sugar with flour and tapioca in grinder until tapioca is powdery, then transfer to a large bowl and stir in remaining 6 tablespoons sugar. Add peaches, blueberries, and lemon juice and gently toss to coat. Spoon filling into pastry and bake, loosely covered with a sheet of foil, until filling is bubbling in center and crust is golden, about 1 3/4 hours.
Transfer cake in pan to a rack and cool, uncovered, 20 minutes, then carefully remove side of pan.
Cool cake to barely warm or room temperature, then cut into thick wedges with a sharp knife before serving.
cooks’ note:Pastry can be made and pressed into pan 1 day ahead and chilled, wrapped well in plastic wrap. Remove from the refrigerator 30 minutes before filling.