1. Preheat your oven to 200°C (400°F) to ensure it’s ready for baking.
2. In a saucepan, heat the milk over medium heat until warm but not boiling.
3. In a separate bowl, whisk the egg yolks, sugar, and cornstarch until smooth and well combined.
4. Slowly pour the warm milk into the egg mixture, whisking constantly to prevent curdling.
5. Return the mixture to the saucepan and cook over low heat, stirring continuously, until it thickens into a creamy consistency.
6. Remove the vanilla cream from heat, stir in the vanilla extract, and let it cool completely.
7. Roll out the puff pastry on a lightly floured surface and cut it into circles or rings using a cutter.
8. Place the pastry rings on a lined baking sheet, leaving space between each for expansion.
9. Spoon the cooled vanilla cream into the center of each pastry ring.
10. Arrange fresh blueberries on top of the vanilla cream for a burst of flavor.
11. Brush the edges of the pastry with an egg wash to give them a golden finish when baked.
12. Bake in the preheated oven for about 15-20 minutes or until the pastry turns golden and crispy.
13. Remove the pastries from the oven and let them cool slightly before serving.
14. Optional: Dust with powdered sugar or drizzle with a light glaze for extra sweetness.
15. Serve warm and enjoy your delicious blueberry pastry rings with creamy vanilla filling.