By the way, have you ever used Captain Morgan's Spiced Rum (or any other spiced rum) for this recipe?
I would think that you may use any kind of rum with this recipe. Not sure about the spices in the spiced rum, but chocolate tastes good with cinnamon, ginger, etc.
I got this recipe from a friend a few years ago. She brought the cake to a Christmas dessert buffet and many of the guests, myself included, begged her (more like hounded her!) for the recipe.
It's now a New Years tradition in my home. Just what everyone needs--more fattening foods at the very end of the holidays! ;)