<ul> <li>1/2 cup blackberry preserves</li> <li>2 tablespoons cornstarch</li> <li>2 tablespoons brown sugar</li> <li>1/4 teaspoon grated lemon zest</li> <li>1/2 cup fresh blueberries</li> <li>1/2 cup fresh blackberries</li> <li>1/2 teaspoon pure vanilla extract</li> <li>2 sheets frozen puff pastry, thawed</li> <li>1 egg, beaten with 2 teaspoons water</li> <li>2 tablespoons granulated sugar</li> </ul>
Heat the oven to 375°F. In a small mixing bowl, stir together the blackberry preserves, cornstarch, brown sugar, and lemon zest. Fold in the fresh berries and vanilla.Lightly flour a work surface. Roll out the puff pastry sheets into 12-by-12-inch squares. Cut each puff pastry sheet into 4 squares. Lay a pastry square on work surface. Place 2 heaping tablespoons of berry filling in the center of the square. Brush the edges of the pastry with egg wash and fold up all four corners to meet to form a “purse.” Carefully press edges together to seal. Transfer to a cookie sheet. Repeat with the remaining ingredients. Brush the tops with the egg wash and sprinkle with granulated sugar. Bake until golden brown, about 25 minutes.