Preheat your oven to 300°F (150°C) and toast the bread cubes on a baking sheet for 10-15 minutes.

In a large bowl, whisk together the eggs, milk, heavy cream, granulated sugar, light brown sugar, vanilla extract, cinnamon, nutmeg, and salt until smooth.

In a separate bowl, combine the toasted bread cubes with the custard mixture. Let it sit for at least 30 minutes.

Gently fold in caramel sauce and optional nuts until well mixed.

Grease a 9x13 inch baking dish with butter or cooking spray and preheat the oven to 350°F (175°C).

Pour the bread mixture into the prepared baking dish, spreading it out evenly.

Place the baking dish in a larger roasting pan with hot water reaching halfway up the sides of the dish.

Bake for 45-60 minutes or until the top is golden brown and the center has a slight jiggle.

Allow to cool for about 30 minutes before slicing and serving warm with additional caramel sauce or ice cream.