In a large mixing bowl, whisk together eggs, milk, heavy cream, sugar, vanilla extract, cinnamon, and salt.

Add the cubed French bread to the mixture and stir to combine. Pour into a greased baking dish.

In a separate bowl, mix together brown sugar, melted butter, and cinnamon. Sprinkle over the top of the casserole.

Cover and refrigerate overnight.

Preheat the oven to 350°F (175°C).

Bake the casserole for 45 minutes or until golden brown and set in the center.

Let cool for a few minutes before serving.