Heat the water in the double boiler over medium heat. Add in the cup of chocolate. Stirring frequently, heat the chocolate to roughly 90-100 degrees Fahrenheit. Once it hits temperature, remove from the heat and let cool. Stir around to cool faster.
Reheat the chocolate to 88 degrees Fahrenheit, stirring frequently. Turn the heat off but keep warm.
Use a silicone spatula to portion a dollop of chocolate into one of the molds and swirl until the mold is covered.
Try not to go over the sides of the mold too much or the chocolate is more likely to break when popping it out.
Freeze the chocolate for 45 minutes. In the meantime, prep your marshmallows and pan.
Portion out the marshmallows you’ll need (I use 10-12 marshmallows per bomb) so that they’re ready to go.
Remove the bombs from the freezer and (with gloves!), very carefully pop the chocolate out of the mold. Place the halves on a plate.
Heat a nonstick pan to very, very low. Gently press one half of the chocolate into the pan so that the rim becomes heated. Fill the half with marshmallows and press the other half into the pan. Press the two halves together lining them up properly to seal.
Place back into the silicone mold. Repeat with the remaining hot chocolate bombs and pop back into the freezer.
Now, make your topping. Heat the chocolate chips and coconut oil in a double boiler until melted and slightly runny. Use a piping bag or a filler, scoop the chocolate out into it. Let it cool slightly, otherwise, you may melt the chocolate bombs when it’s drizzled on top.
Remove the hot chocolate bombs from the freezer and quickly drizzle the topping over the bomb. Add any crunch on top that you want too.
Place back in the freezer for ten minutes to set. Portion into however you wish to store the bombs!