Grease a 9x13 inch casserole dish with butter or non-stick spray.

Cut day-old bread into 1-inch chunks and place them in a large mixing bowl.

Whisk together the eggs, milk, heavy cream, brown sugar, granulated sugar, vanilla extract, and ground cinnamon until smooth.

Pour the custard mixture over the cubed bread and gently fold in chopped bananas.

Spread the mixture in the greased casserole dish, cover with plastic wrap, and refrigerate overnight.

Preheat the oven to 350°F (176°C). Let the casserole sit at room temperature for 15-20 minutes.

Bake for 35-40 minutes until golden brown and slightly soft in the center.

If using a streusel topping, mix all-purpose flour, brown sugar, and melted butter, sprinkle on top after 30 minutes of baking.

Let sit for a few minutes before serving and top with maple syrup, whipped cream, or fresh fruit.