1. In a small saucepan, bring the brown sugar, butter, and corn syrup to a boil over medium heat, stirring constantly. Allow to boil for 1 to 2 minutes.
2. Pour mixture into a greased 9x13 in cake pan.
3. Top with six slices of bread.
4. Combine sugar and 1/2 tsp cinnamon. Sprinkle half over the bread.
5. Place remaining bread on top. Sprinkle with remaining cinnamon-sugar.
6. In a large bowl, whisk the eggs, milk, vanilla, and remaining cinnamon. Pour over bread.
7. Cover and refrigerate for 8 hours or overnight.
8. Remove from the refrigerator 30 minutes before baking.
9. Bake at 350º for 30 to 35 minutes.