Preheat oven to 400 °F (200 °C) and line a baking sheet with parchment paper.

In a small bowl, beat together cream cheese, sugar, and vanilla until smooth and creamy. Set aside.

In another bowl, gently toss diced strawberries with strawberry jam and lemon juice; set aside.

On a lightly floured surface, unfold puff pastry and gently roll out to smooth seams. Cut into 4 equal squares.

Spread a thin layer of the cream cheese mixture in the center of each square, leaving a ½‑inch border.

Spoon strawberry mixture over the cream cheese layer.

Fold two opposite corners of each pastry square over the filling, overlapping slightly in the center.

Mix beaten egg with water and brush over pastry edges to create a golden finish.

Bake for 18–20 minutes, or until pastries are puffed and golden brown.

Remove from oven and cool on baking sheet for 5 minutes before transferring to a wire rack to cool slightly.

Serve warm or at room temperature.