Preheat oven to 400ºF and line a large baking sheet with parchment paper. In a shallow dish, whisk eggs, eggnog, bourbon, melted butter, brown sugar, cinnamon and nutmeg. Dunk each slice of bread into egg mixture and let excess custard run off bread back into dish.
Place slices on prepared baking sheet. Bake for 8 minutes. Carefully flip bread and return to oven for 8 minutes longer.
To ensure food safety, eggs should be cooked until both the yolk and the white are firm. Consuming raw or undercooked eggs may increase your risk of foodborne illness, especially for those with certain medical conditions. For recipes that call for eggs that are raw or undercooked when the dish is served, use either pasteurized shell eggs that have been treated to destroy Salmonella, or use pasteurized egg products.