For the pastry:
- 2 1/4 cups all-purpose flour
- 1/4 cup sugar
- 1/2 teaspoon ground cardamom
- 1/4 teaspoon salt
- 1 1/2 sticks unsalted butter (about 6 ounces)
- 3 1/2-4 tablespoons cold water
- 6 amaretti cookies, crushed
For the filling:
- 1 pint blueberries
- 2 cups ripe nectarines, diced
- 3 tablespoons sugar
- 2 tablespoons cornstarch
- 1 tablespoon heavy cream
- 1 egg yolk, beaten with heavy cream
- 6 teaspoons coarse raw sugar
- Gelato (optional)
- Lightly sweetened whipped cream (optional)
In a food processor, combine the flour, sugar, cardamom and salt. Pulse to combine. Add the butter and pulse to pea size. Sprinkle 3 tablespoons water over the flour. Process for 3-4 seconds, until starting to come together (if the dough looks very sandy, add water and pulse a few more times until clumping but slightly loose).
Turn the dough out onto a large sheet of plastic wrap. Bring the wrap up and cover the top of the dough. Press to form 7-inch disk. Chill until cold.
Divide the dough into six equal pieces. Roll out on a lightly floured board to form 1⁄8-inch-thick circles approximately 5 inches in diameter.
Line a baking sheet with parchment paper.
Transfer the circles to the sheet.
Spoon the cookie crumbs into the center of the circles.
In a large bowl, gently toss the blueberries, nectarines, sugar and cornstarch.
Mound the fruit evenly in the center of each circle, leaving a 1-inch border around the edges.
Bring the pastry up and over filling, just to form a 1-inch border.
Brush the pastry lightly with the egg mixture and sprinkle with sugar. Chill until cold.
Position the oven rack in the lower third of the oven. Pre-heat the oven to 425°F.
Bake the crostata for 35 minutes, until the center lightly bubbles and the crust is deep golden.
Cool for 15 minutes.
Serve warm with gelato or lightly sweetened whipped cream.