Preheat oven to 350. Lightly coat an 8x8 inch square baking dish with nonstick spray.
Place bread pieces inside dish and drizzle with the melted butter.
In a medium mixing bowl, combine eggs, milk, both sugars, vanilla, and cinnamon; whisk until well blended.
Pour liquid mixture over bread, and lightly push down with a spatula (or your hands) until bread is covered and soaking up the egg mixture.
Bake for 40-45 minutes, or until the top springs back when lightly tapped. Let stand for 10 minutes before serving.