Place croissant pieces in a 9 inch square pan. Sprinkle with blueberries.
Beat cream cheese, sugar, eggs and vanilla in medium bowl with electric mixer until well blended. Gradually add milk, beating well after each addition. Pour evenly over croissant pieces. Let stand for 20 minutes.
Bake at preheated 350°F oven for 35 to 40 minutes or until set in center and golden brown. You may want to cover it with foil for the last 10 minutes if the tops are getting too browned. Let cool in the pan for few minutes.