For the puff pastry crumble with vanilla, remove puff pastry from refrigerator about 10 minutes before processing and preheat oven to 200 °C. Unroll puff pastry, brush with beaten egg and prick with a fork. Bake in the oven for about 15 minutes on the middle rack. Remove and let cool.
Cut with a serrated knife about 2 cm pieces and set aside. For the cream, bring milk, granulated sugar, vanilla bean and pulp to a boil. Mix vanilla cream powder, egg yolks and 2 tablespoons milk, stir into the milk and bring to a boil, stir until cold.
Fold in whipped cream and layer alternately with puff pastry pieces, blueberries and the vanilla cream in glasses, garnish with mint and serve.