1. Grease a 9 x 13 casserole dish with butter.
2. Tear bread into chunks and evenly lay out in dish.
3. Whisk together eggs, milk, cream, cake mix, cinnamon, vanilla and 3 1/2 tbsp sprinkles. Pour evenly over bread.
4. Cover and store in fridge for several hours or overnight.
5. In another bowl, add cake mix and butter for topping. Mash until it all comes together. You can store this mixture in the fridge overnight if you’d like.
6. Preheat oven to 350 degrees the next morning.
7. Remove casserole and pre-made topping from fridge. Crumble pre-made topping and sprinkle over the top of the casserole. Sprinkle remaining 1 1/2 tbsp sprinkles over top of the pre-made topping.
8. Bake for 45 minutes for a softer, more moist texture. Bake an hour or more for a firmer, less moist texture.
9. Serve with syrup or rainbow chip icing that has been warmed up a little to allow easy pouring.