Melt butter. In a sauce pan melt butter, then mix in brown sugar and maple syrup. Stir the mixture until it begins to boil then remove it from the heat.
Place the bread cubes in a large bowl. Place the bread cubes in a large bowl and pour the cooked sugar mixture over them. Toss until it is well distributed. Place the bread cubes in the baking dish.
Whisk together. In a large bowl whisk together egg, eggnog, vanilla, cinnamon, nutmeg, and rum extract or dark rum if you are using it.
Pour egg mixture. Pour egg mixture over the bread cubes. Cover the baking dish with plastic wrap and place it in the refrigerator for at least 1 hour up to overnight.
Bake preheat the oven to 350°F. Remove plastic wrap. Cover with aluminum foil. Place baking dish in the over for 35 minutes, then uncover and bake for another 15 -20 minutes, or until top is golden brown.