Preheat oven to 350F.
Using the stick of unsalted butter, liberally grease the bottom and sides of a cast iron skillet.
In a large bowl, whisk together eggs, milk, heavy cream, sugar, brown sugar, bourbon, vanilla, salt, nutmeg, and cinnamon.
Add cubed bread to cast iron skillet in an even layer. Pour liquid mixture over the bread, allowing it to sit for 10 minutes.
Bake for roughly 45-50 minutes -- or until the bread pudding has fully set. Allow bread pudding to cool/rest for 10 minutes.
Garnish with whipped cream, fresh berries, and fresh mint. Enjoy!