Preheat oven to 350°F (if baking immediately). Arrange bread in a single layer in a greased 13 x 9-inch baking dish.
Beat eggs slightly in a medium bowl. Stir in milk, corn syrup, butter, cinnamon and vanilla until smooth. Pour over bread. Bake immediately OR cover and refrigerate several hours or overnight.
Bake uncovered at 350°F for 30 minutes. Remove slices from baking dish and invert onto plates. Top with powdered sugar and/or pancake syrup, if desired.
