Butter shallow baking pan and arrange the bread in a single layer. Beat together the eggs, egg whites, milk, sugar, cinnamon, syrup, vanilla, and salt in a large bowl.

Pour mixture over bread. Turn slices to coat. Cover with plastic and refrigerate overnight. Preheat oven to 400°F. Bake the French toast for 20 minutes or until a tester inserted in the center comes out clean.

Turn the bread and continue baking until golden, about four minutes longer. Transfer to a warm plate and sprinkle with powdered sugar.

TESTER'S NOTE: Eggnog makes amazing overnight French toast. Add 2 whole eggs, lightly beaten, to 2 cups of Eggnog. Pour over thick slices of bread. Turn bread to coat. Bake in the morning, as instructed above. Serves 8.