1. Grease a 9×13 inch casserole dish.
2. Add the bread chunks to a large bowl and set aside.
3. In another large bowl, whisk together the eggs, milk, cream, sugars, vanilla extract and cinnamon.
4. Pour the egg mixture over the bread chunks and add the chopped banana, then gently stir to combine everything.
5. Pour the bread mixture into the prepared casserole dish and spread evenly in the pan. Cover the casserole and store in the fridge overnight.
6. When ready to bake the casserole, preheat the oven to 350°F (176°C).
7. Bake the casserole for about 35-40 minutes, or until it’s at your desired level of doneness.
8. While the casserole bakes, combine the dry ingredients for the streusel, except for the butter.
9. Add the butter and mash into the dry mixture until it forms a crumbly mixture.
10. When the casserole looks about done, remove the casserole from the oven and crumble the streusel over the top of the casserole.
11. Continue baking the casserole for about 5 minutes, or until the streusel is melted over the top.
12. Serve the casserole warm with syrup.