In small bowl, combine melted chocolate, sour cream, and salt. Mix until smooth.
In a large mixing bowl, combine wafers and almond paste with all remaining dry ingredients. You want everything to be as evenly mixed as possible before moving on to the next step.
Add chocolate mixture and your rum. Mix until everything is combined and your "dough" is smooth and soft. Refrigerate for at least 5 hours, but preferably overnight.
Roll the mixture into balls. We measured ours out to be around 20 grams each, which is approximately 2 tbsps, or roughly the size of a ping-pong ball. Place the balls on waxed paper and chill again until it's time to coat them.
Tip: Depending on what sort of alcohol you've used (see note), your dough will get soft rather quickly while you're rolling it into the balls. Feel free to roll it in smaller batches if needed.
Mix up your coating(s). We did some with powdered sugar and a pinch of cinnamon, and some with a blend of cocoa and powdered sugar. Put your coating in a small bowl, add a ball, and roll it around in the powdered coating.
Depending on what sort of alcohol you're using, your dough's consistency can be thinner and more prone to softening if left at room temperature. Something creamy, like Rum Chata, will yield a firmer dough to roll.
This recipe will make about 5 lbs of rum balls. It's insane. When stored in an airtight container and kept chilled, these little balls will last a long time. The Beard and I made these a week before Christmas, and we still have some in our fridge in the middle of January. I expect that their shelf-life, if frozen, could rival that of a Twinkie.
The flavor of these will get better as they mellow in your fridge or freezer. For best results, roll them into balls, chill them for a week, then roll them in the coating.