Heat the Heavy Cream (1/2 cup) until in just bubbles. Pour over the Dark Chocolate (10 ounce) and Rum (1/4 cup). Mix well with a rubber spatula. If you still have lumps, put the bowl over a bain marie and mix until smooth.
Chill in the refrigerator for 1 hour.
Put each of your coatings (cocoa powder, nuts, coconut) in a separate bowl.
Roll the chocolate into 1-tablespoon size balls. Immediately roll in the Pistachios (to taste), Hazelnuts (to taste), or Coconut (to taste). If you wait, the nuts won't stick as well.
Keep in the refrigerator. Take out of he refrigerator 30 minutes before enjoying!