To make the hot chocolate powder, combine all of the ingredients in a small bowl or jar (a mason jar works well for this).

Store at room temperature until ready to use. 

Melt the chocolate candy coating according to the package directions. 

Fill each of the wells with 1-2 tablespoons of melted chocolate. Spread the chocolate around using a spoon or small offset spatula. Don’t forget to spread the chocolate all the way to the top-- you want to have a thick edge so your chocolate bomb doesn’t break. 

Place the chocolate in the fridge for 5 minutes, or until it has hardened completely. 

Carefully remove the chocolate wells from the mold. 

Fill half of the chocolate wells with hot chocolate powder and mini marshmallows. 

Heat a nonstick pan over medium-high heat until it is barely warm. 

Place the rim of unfilled chocolate onto the pan for 1-2 seconds, or until the edges start to melt. 

Carefully remove the chocolate from the pan and place it on top of the filled chocolate well. Press gently to seal the two together. 

Decorate with melted chocolate and sprinkles, if desired. 

To serve, add a hot chocolate bomb to a large mug. Pour over hot milk and stir until all of the chocolate has melted.