If raspberries are not available, you can substitute blueberries. Note: You must start this dish one day ahead.
To make French Toast: Grease 9×13-inch baking dish. Place 6 slices bread evenly on bottom of pan, and dot with half of cream cheese. Layer remaining 6 slices on top, and dot with remaining cream cheese.
Whisk together eggs, milk, syrup and raspberries in mixing bowl. Pour egg mixture over bread. Cover baking dish with foil, and refrigerate overnight.
Preheat oven to 350F.
Bake bread 1/2 hour covered; remove foil, and bake 30 minutes more, or until bread begins to puff up and brown.
To make Raspberry Sauce: Combine sugar, cornstarch and 1 cup water in saucepan, and bring to a boil. Reduce heat to medium, and cook 3 minutes, or until thickened. Whisk in raspberries, and cook 3 minutes more, or until sauce has thickened again. Serve French Toast with Raspberry Sauce.