Thaw the puff pastry sheets according to the package instructions.
2 sheets puff pastry
Preheat the oven to 200°C (400°F). Line a baking sheet with parchment paper.
In a large bowl, mix together room-temperature cream cheese, sugar, egg yolk, and vanilla extract. Beat with a mixer on low speed until smooth.
8 oz cream cheese, ¼ cup granulated sugar, 1 egg yolk, 1 tsp vanilla extract
Unfold one sheet of puff pastry and lightly roll it into a 10x10-inch square. Cut it into 9 equal squares.
Fold each corner of the pastry square towards the center and gently press to adhere, creating a folded shape. Prick the centers with a fork.
Place a spoonful of the cream cheese mixture in the center of each pastry and press a couple of blueberries and strawberries into the cream.
½ cup blueberries, ½ cup strawberries
Transfer the pastries with the filling onto the prepared baking sheet, leaving some space between them.
In a small bowl, whisk together the egg and milk. Brush the outer edges of the pastries with the egg wash.
1 egg, 1 tbsp milk
Bake for about 20 minutes. Allow them to cool completely.
In another small bowl, mix powdered sugar and milk to make the glaze. Drizzle the glaze over the cooled pastries.
¼ cup powdered sugar, 2 tbsp milk