Ingredients
Method
Step-by-Step
- Heat the oven to 400°F (200°C) and line a baking sheet with parchment paper.
- Gently combine the blackberries, granulated sugar, cornstarch, lemon juice, lemon zest, and salt. Let the mixture stand for about 5 minutes so the berries begin releasing their juices.
- Cut the thawed puff pastry into six rectangles or squares. Lightly score a 1/2-inch border around each piece without cutting completely through the pastry.
- Arrange the pastry pieces on the parchment-lined baking sheet. Spoon the blackberry mixture into the centers, keeping the fruit inside the scored borders.
- Beat the egg with the water, then brush the exposed pastry edges with the egg wash. Sprinkle the edges with coarse sugar if desired.
- Chill the assembled tarts for 10–15 minutes. This short rest helps the puff pastry stay cold and hold its shape in the oven.
- Bake for 20–25 minutes, until the pastry is puffed and deeply golden and the blackberry juices are visibly bubbling.
- Cool the tarts for at least 10 minutes before serving. Finish with confectioners’ sugar or serve with whipped cream.
Notes
Keep the puff pastry cold throughout assembly. If it becomes soft, refrigerate the assembled tarts before baking. Cornstarch helps thicken the blackberry juices, so allow the baked tarts to cool before serving. For especially tart berries, use 1/2 cup sugar; for very sweet berries, 1/3 cup is usually sufficient.
