Nectarine and Blueberry Crostata with Polenta Crust

by Sarah Lagrotteria 

Photo by Ryan Benyi 

Photo by Ryan Benyi 

(adapted from Bon Appétit Magazine)

Serves 8

12⁄3 cups all-purpose flour
1⁄4 cup polenta (coarse cornmeal)
3-1/2 tablespoons sugar
Zest of 1 orange
3⁄4 teaspoon salt
14 tablespoons (13⁄4 sticks) chilled unsalted butter, cut into 1⁄2-inch cubes
1⁄3 cup (or more) ice water

Filling and baking
3 teaspoons thyme simple syrup (see recipe below)
2 teaspoons cornstarch
4 medium nectarines, each pitted and cut into 16 slices
1 pint blueberries
1 egg, lightly beaten
Sugar in the raw, for sprinkling

For crust
Pulse the first five ingredients (flour through salt) in the bowl of a food processor. Add the chilled butter and pulse until butter is just reduced to pea-size pieces. Add 1⁄3 cup ice water and continue pulsing until the dough comes together in wet clumps. Turn out the dough onto a parchment paper sheet and roll into a ball. Flatten, wrap and chill for at least one hour and up to 24. 

Let the dough soften to near-room temperature. Roll on a lightly floured sheet of parchment paper to a 14-inch round, turning dough occasionally to prevent sticking. Place the parchment on a baking sheet. Transfer the dough on the parchment to the refrigerator. Chill until dough firms slightly, about 30 minutes.

For filling and baking
Stir together the simple syrup and cornstarch in a medium-sized bowl. Fold in the fruit and let stand until juices are released, stirring occasionally, about 30 minutes. Preheat the oven to 375°. Transfer the baking sheet with dough to work surface. Spoon fruit and juices into the center of the dough. Spread fruit into an even 10-inch diameter layer in the center of the tart. Brush the remaining 2-inch border with egg wash. Gently fold the border up and over the edge of the fruit, overlapping crust when necessary to create a pleat. Brush the crust with the remaining egg wash and sprinkle with sugar in the raw. 

Bake until crust is golden brown and fruit filling is bubbling at edges, about 50 minutes. 

Remove from oven; slide large metal spatula under tart to loosen from parchment. Slide tart onto a rack to cool. Serve warm or at room temperature.

Thyme Simple Syrup

Makes approximately 1 cup 

1 cup sugar
1 cup water
1 bunch fresh thyme

Combine all three ingredients in a heavy-bottomed saucepan. Bring to a boil and simmer until the sugar dissolves, about 2 minutes. Remove from the heat and let cool. Discard thyme and strain the syrup to remove any loose leaves. Store in refrigerator for up to one week.