Preheat oven to 350°F (175°C). Grease a medium baking dish.
Place bread cubes into the dish.
In a large bowl, whisk eggs, milk, sugar, vanilla, cinnamon, and nutmeg until smooth.
Pour custard mixture evenly over bread cubes, pressing gently so bread absorbs the liquid.
Let sit for 10 minutes to soak.
Bake uncovered for 40–45 minutes, or until the top is golden brown and the custard is set but slightly soft in the middle.
To make bourbon sauce: In a saucepan, melt butter and sugar over medium heat, then stir in cream and bourbon. Cook until slightly thickened.
Serve bread pudding warm with bourbon sauce, whipped cream, or ice cream.