Line a large baking sheet with parchment paper or silpat. Pre-heat the oven to 375 degrees F. When the dough is malleable, but still firm use your hands to form a ball with one piece of dough, keeping the second disk of dough in the refrigerator. Flatten the ball and place between 2 pieces of plastic wrap. Roll out into a circle about 9-10 inches in diameter. Transfer to the refrigerator. Continue to roll out the remaining dough. Place a circle of dough on the baking sheet, leaving room for the other crostata. Spoon about 1/2 cup of the berry mixture onto the circle, leaving at least 1-inch border. Bring the edges of the dough over the top to envelop the berries. Using your hands, fold in the edges, pressing gently and patching any holes. Cup your hands over the tart and press down firmly to shape. Repeat with remaining dough and berries. Chill both tarts for about 20 minutes before baking.