01 - Preheat the oven to 400°F and line a baking tray with parchment paper.
02 - In a small bowl, combine softened cream cheese, granulated sugar, vanilla extract, and lemon zest. Mix until smooth and creamy. Set aside.
03 - In a separate bowl, toss diced strawberries with granulated sugar, lemon juice, and cornstarch. Set the mixture aside.
04 - Roll out the sheet of puff pastry and cut into 8 equal squares. Using a knife, lightly score a 1/2-inch border around each square without cutting all the way through.
05 - Place one tablespoon of cream cheese filling in the center of each pastry square and gently spread within the scored border. Top each with a tablespoon of strawberry mixture.
06 - Combine beaten egg with milk. Using a pastry brush, lightly brush the borders of each pastry square with the egg wash.
07 - Transfer the prepared pastries to the baking tray and bake for 18 to 22 minutes, or until puffed and golden brown.
08 - Remove pastries from the oven and cool slightly on a wire rack.
09 - In a bowl, whisk powdered sugar with 2 to 3 teaspoons of milk and vanilla extract until the mixture is smooth. Drizzle glaze over cooled pastries as desired.