French Toast Casserole

Place bread cubes in a greased 13x9-in. baking dish. In a large bowl, whisk the eggs, milk, sugar, vanilla and salt. Pour over bread. Cover and refrigerate for 8 hours or overnight. , Remove from refrigerator 30 minutes before baking. Preheat oven to 350°. Dot with butter. Combine sugar and cinnamon; sprinkle over the top. , Cover and bake until a knife inserted in the center comes out clean, 45-50 minutes. Let stand for 5 minutes. Serve with maple syrup if desired.