Mix all dry ingredients except brown sugar in a medium mixing bowl and set aside. In a separate larger mixing bowl combine butter, molasses, brown sugar, and boiling water. Stir until liquids are well incorporated. Once this mixture cools, add egg and stir. (Adding egg while mixture is still hot may cook the egg).
Add dry ingredients to liquid mixture. Whisk together until there are no lumps.
Pour in molds, but take care not to fill entirely to the top to prevent overflow (leave about 1/4"). Bake at 350°F for 30-35 minutes.
Allow cakes to cool, then trim any cake that rose above the mold. This will give you a flat surface when you flip the cake houses over onto a plate.
Once we popped out cakes out of their molds, we decorated them with white chocolate, candy, and coconut "snow." This part is left up to your imagination!
To decorate:
We started by trimming the houses with white chocolate, then we used white chocolate as the "glue" to attach candy to the houses. We arranged our houses on a cake stand like a little village and sprinkled dry coconut flakes liberally to look like fresh snow.