If preparing gingerbread cake from mix, make and bake according to box directions.
Once the cake is cooled, cut into cubes.
Allow cake to sit uncovered overnight or place on baking sheet and toast in 250 oven for about 25 minutes.
You want the gingerbread cake to be stale or some what dried out so that it soaks up all of the liquid.
Combine milk, eggs, cinnamon, ginger, salt, vanilla extract and brown sugar in a large mixing bowl. Whisk until ingredients are combined.
Add cubed gingerbread to mixture, pressing down to make sure all of bread is covered. Place in the refrigerator to soak for 45 minutes.
Preheat the oven to 350.
Prepare an 8 inch square pan by placing butter in the baking dish and putting it in the heated oven.
Allow butter to melt and remove dish from the oven.
Pour soaked bread into prepared baking dish.
Bake for 35-40 minutes, or until bread pudding is set.
While bread pudding is baking, make the eggnog sauce.
Add eggnog and flour to a saucepan, whisk together. Add butter, sugar and nutmeg.
Heat mixture over medium heat, stirring frequently until mixture comes to a boil.
Boil for 2 minutes. Remove mixture from the heat and mix in vanilla. Set aside.
When bread pudding is set, remove from oven and allow to cool for 15 minutes. Serve with eggnog sauce.
This bread pudding does not call for a lot of sugar because the sauce adds sweetness, if you do not plan on serving a sauce with this recipe, I would suggest increasing the brown sugar to 1/2-3/4 cup depending on how sweet you want your bread pudding to be.