Place bread cubes ina 13 x 9 x 2 inch baking dish coated with nonstick cooking spray.
In a bowl, combine the egg whites, eggs, milk, surgar, cinnamon, vanilla and salt; pour over bread.
Cover and refrigerate for 8 hours or overnight.
Thirty minutes before baking, remove the berries from the freezer, set aside, and remove the baking dish from the refrigerator.
Bake, covered, at 350 degrees for 30 minutes.
In a small bowl, cut butter into brown sugar until crumbly. Sprinkle berries and brown sugar mixture over french toast. Bake, uncovered, for 15-20 minutes or until a knife inserted near the center comes out clean.