Place bread cubes in a 13-in. x 9-in. baking dish coated with cooking spray. In a large bowl, combine the egg whites, eggs, milk, sugar, 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 and set aside, and remove the baking dish from the refrigerator. Bake, covered, at 350Â° 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.