01 - Preheat oven to 400°F and line a baking tray with parchment paper.
02 - In a small bowl, combine cream cheese, granulated sugar, vanilla extract, and lemon zest. Mix until smooth and creamy. Set aside.
03 - In a separate bowl, gently toss diced strawberries with granulated sugar, lemon juice, and cornstarch until evenly coated. Set aside.
04 - Roll out puff pastry sheet and cut into 8 equal squares. Lightly score a ½-inch border around each square without cutting through.
05 - Spoon 1 tablespoon of cream cheese filling into the center of each pastry square, spreading gently within the scored border.
06 - Top each with 1 tablespoon of the strawberry mixture, keeping filling inside the border.
07 - Brush the borders of each pastry with egg wash made by whisking together the beaten egg and milk.
08 - Bake pastries for 18–22 minutes or until puffed and golden brown.
09 - Remove from oven and transfer pastries to a wire rack. Allow to cool slightly.
10 - Whisk powdered sugar, 2–3 teaspoons milk, and vanilla extract until smooth. Drizzle over cooled pastries if desired.