Spray a 13x9" baking pan with cooking spray and set aside.
Slice loaf of bread into 1 inch cubes and place in prepared baking pan.
In a medium mixing bowl, combine eggs, milk, cream, granulated sugar, bourbon, vanilla and cinnamon. Whisk to combine well.
Pour mixture in an even layer over the bread, soaking it.
Tightly cover baking pan with plastic wrap and place in refrigerator overnight.
TO MAKE THE TOPPING:
To a food processor, add all topping ingredients except for the butter. Pulse it a couple times to combine. Add in cold cubed butter and pulse until butter is cut into the mixture and it resembles coarse, pea-sized crumbs.
Place in a plastic bag in the refrigerator overnight.
Preheat oven to 350 degrees F.
Take baking pan out of the refrigerator and let sit at room temperature for 10 minutes or so while the oven is preheating.
When oven is ready, remove plastic wrap from baking pan. Take the plastic bag with the topping out of the refrigerator and sprinkle evenly over the top of the bread.
Bake for 45 -60 minutes. If you like your casserole to be soft, bake for 45. If you like it to have a good crunch to it, bake it for 60.
Serve drizzled with warm maple syrup and sprinkled with powdered sugar if desired.