Heat oven to 350°F. Grease a 9-inch square baking dish with a little butter.
Whisk eggs, granulated sugar, brown sugar, salt, cinnamon, and nutmeg in a large bowl until smooth.
Whisk in milk, cream, vanilla, melted butter, and bourbon until the custard is well combined.
Add bread cubes to the bowl and toss to coat. Let soak 10 minutes, stirring once.
Fold in raisins and pecans. Transfer mixture to the prepared dish and press down to submerge bread.
Bake 40–45 minutes, until puffed, golden, and the center is just set.