Eggnog Bread Pudding

4 large eggs
2 1/2 cups store-bought eggnog
1/4 cup brown sugar
2-4 tbs dark rum
1 lb day old cinnamon-raisin bread, about 12 slices
softened butter for bread and baking dish
Butter an 8-inch square baking dish. In a medium bowl, whisk together eggs, eggnog, brown sugar, and rum.
Moderately butter one side of each slice of cinnamon-raisin bread and cut into 1/2 cubes. Place bread in prepared dish and pour eggnog mixture over top. Let stand for five minutes. Gently push bread down into custard. Refrigerate for 2 hours, occasionally pushing bread down into custard.
Preheat oven to 375F. Place bread pudding dish into a larger baking dish. Add enough boiling water to bottom pan to come 1 inch up the side of the dish with the bread pudding. Bake until pudding is puffed up and golden brown, about 50 minutes. Remove dish from water bath and let cool slightly. Cut into squares. Serve pudding with warm eggnog.