Heat the chocolate over a double boiler. This can be done in the microwave, but I find that when you do it over a double boiler you get a smoother product with less chance of overheating.
Pour the chocolate into a plastic piping bag. Cut the very tip off, but keep the whole very small.
Place the tip into the hole on the top of the ice cube mold. Fill with chocolate and repeat on all of the other holes in the mold.
Make sure the top is on tightly and flip the mold over and drain out of the top hole back into the bowl with the melted chocolate. Place the mold into the freezer for about 30 minutes to an hour or up to over night.
Remove the molds from the freezer and carefully un-mold them.
Place a small funnel into the top of the hole and fill with the hot cocoa mix.
Take your piping bag with melted chocolate and lightly fill the top of the small hole to close the circle completely. Let it dry for a few minutes or stick it back into the freezer.
Melt your white chocolate and drizzle over the top of the bombs. I also sprinkled some black onyx chocolate sugar over mine. You can use sanding sugar or nothing is fine too
**If you would like to add marshmallows into the bombs, you can gently make the top hole large enough to fit the marshmallows into the hole. Then instead of filling the hole to seal it, lightly dab some chocolate with a spoon over the hole and seal it that way. ENJOY!