Cook strawberries with sugar, cornstarch, and lemon juice for 5 to 7 minutes until thick, then cool completely.
Beat cream cheese and sugar until smooth, mix in egg yolk, vanilla, and flour, then chill briefly.
Unfold puff pastry on a floured surface and cut into rectangles or squares, keeping it cold.
Add cheesecake filling and strawberry filling to the center, fold, seal, and crimp the edges.
Brush with egg wash, sprinkle with sugar if desired, and bake at 400°F for 15 to 18 minutes until golden.
Cool slightly, drizzle with glaze, let set, and serve.