Grease a 9x13x2" baking pan. Arrange 1" bread slices evenly in the pan.
Beat together the 3 eggs, 3 c. milk, 4 t. sugar, 3/4 t. salt and 1 T. vanilla. Pour over the bread evenly.
Cover and refrigerate overnight.
Before baking, preheat oven to 350 degrees. Uncover and dot the top with 1 T. butter, sprinkle with 1 T.cinnamon.
Bake 350 degrees for 45 minutes.
Cut into squares and serve immediately with warmed maple syrup.