01 - Preheat the oven to 400°F and line a baking tray with parchment paper.
02 - In a small bowl, mix cream cheese, granulated sugar, vanilla extract, and lemon zest until smooth and creamy. Set aside.
03 - In a separate bowl, toss diced strawberries with granulated sugar, lemon juice, and cornstarch until evenly coated. Set aside.
04 - Unfold the puff pastry and cut into 8 equal squares. Score a 1/2-inch border around each square without cutting all the way through.
05 - Place 1 tablespoon of cream cheese filling in the center of each square and gently spread within the border.
06 - Spoon 1 tablespoon of strawberry mixture over the cream cheese layer on each square.
07 - Brush the pastry borders with egg wash made from the beaten egg mixed with milk.
08 - Bake in the preheated oven for 18 to 22 minutes, or until pastries are puffed and golden brown.
09 - Remove pastries from the oven and let cool slightly on a wire rack.
10 - For the optional glaze, whisk powdered sugar, milk, and vanilla extract until smooth. Drizzle over cooled pastries as desired.