Arrange half the bread in a single layer in a greased 13x9-in. baking dish; top with cream cheese. Top with remaining bread.
In a large bowl, whisk eggs, milk, 1/3 cup syrup, cinnamon and nutmeg until blended. Pour over casserole. Refrigerate, covered, overnight.
Remove casserole from refrigerator 30 minutes before baking. Preheat oven to 350°. Bake, uncovered, until a knife inserted in center comes out clean, 50-60 minutes. Let stand 10 minutes before serving. If desired, serve with additional maple syrup.