Follow these easy steps to create your delicious Easy Blackberry Turnovers:

1. Preheat Oven: Begin by preheating your oven to 375°F (190°C). Line a baking sheet with parchment paper.
2. Prepare Filling: In a mixing bowl, combine fresh blackberries, granulated sugar, cornstarch, vanilla extract, and lemon juice. Gently toss until the blackberries are evenly coated.
3. Roll Out Pastry: Unroll the thawed puff pastry on a lightly floured surface. Cut it into 4 squares (about 4×4 inches).
4. Add Filling: Place a tablespoon of blackberry filling in the center of each pastry square.
5. Fold and Seal: Fold the pastry over the filling to create a triangle shape. Press the edges to seal tightly. You can use a fork to crimp the edges for a decorative touch.
6. Prepare Egg Wash: In a small bowl, whisk together the egg and milk. Brush the egg wash over the tops of the turnovers for a golden finish.
7. Bake: Arrange the turnovers on the prepared baking sheet and bake in the preheated oven for 25-30 minutes, or until golden brown and puffed up.
8. Cool: Remove from the oven and allow to cool slightly on a wire rack. Dust with powdered sugar if desired before serving.

With these steps, you’ll have a batch of Easy Blackberry Turnovers that will tantalize your taste buds and impress all who try them!