Slice croissants and place four halves in bottom of 8 x 12 sprayed pyrex. Spread slightly warmed cream cheese on the 8 halves. Sprinkle 1 1/2 cups of the blue berries on croissant halves in pan. Place other halves on top.
Beat together eggs, syrup and milk. Pour over croissants.
Cover with plastic wrap. Press down, making sure croissants are soaked through with mixture. Refrigerate overnight.
Preheat oven to 350 degrees. Bake 45 minutes covered with tinfoil. Bake 15 minutes uncovered.
This syrup/sauce can be made ahead of time if desired.
Mix 1 1/2 cups blueberries with water, sugar and cornstarch. Cook until medium thickness. Take off stove and add the butter.
Cut into four croissant sections. Spoon syrup/sauce over each serving. May top with a touch of whipped cream or a sprig of mint.