Once bread pudding is assembled, cover tightly with foil and let rest in the fridge overnight or up to 8 hours.
Prior to baking, remove foil, add reserved bread cubes to the top of the pudding. Sprinkle with 1 TBSP reserved sugar, dot with melted butter. Let rest at room temperature for 30 minutes prior to baking.
Pre- heat oven to 375 degrees. Keep bread pudding covered. Bake at 350 degrees for 30 minutes. Reduce oven temp to 350 and bake uncovered for another 20-25 minutes or until the custard is set and an instant read thermometer reads 170 degrees.
Let rest (covered) on a wire rack for 30 minutes prior to serving.
Serve warm with Bourbon vanilla sauce poured over.
Serves 8-10.