Peach and Blueberry Cake

This cake bakes for a long time at a moderate temperature, which helps keep the ripe fruit from bursting and releasing its juices. The easy-to-make pastry bakes up moist and crumbly, with a texture that's like a cross between a biscuit and a cake.

For pastry

• 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

For filling

• 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) spring form pan; an electric coffee/spice grinder

Make pastry:

• 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 spring form 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 375ºF.
• 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’ notes:

• 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.
• 
  
• Baked in a standard light-colored metal pan, the cake is fine; baked in a dark metal pan, it seems to burn — note that the cake’s high sugar content makes it more susceptible to burning at a higher temperature. Recommend: always using light-colored metal pans for baking. Dark metal pans, including nonstick, will cause your baked goods to brown more quickly. Reduce the oven temperature by 25 degrees when using dark pans.