Toss the raspberries with cornstarch and granulated sugar in a mixing bowl. Set them aside. Roll out the thawed puff pastry gently and then cut each sheet into equal squares. Fold over the corners of each of the squares to create an octagon.
Scoop the cream cheese mixture onto the center of each puff pastry. Beat the egg wash mixture together and then brush it all over the pastry around the cream cheese filling. Next, flatten the dollops of cream cheese, spreading it out carefully.