Use a double boiler or set a bowl over a pot of simmering water and combine the semi-sweet and milk chocolate chips in it. Make sure the vessel does not touch the water. Gently stir until the chips have melted.

Spoon about a Tablespoon of chocolate into each mold and using a spoon, swirl the chocolate to coat the entire inside of the mold. Use a knife to swoop across the mold and clean off any extra and then place the mold upside down on parchment paper. When all the molds are filled, either freeze for about 5 minutes or refrigerate for 10 minutes.

Repeat the same process with the chilled molds so that you have two coats; making sure there is a nice amount at the lip of the chocolate. Freeze or refrigerate again.

Gently remove the chocolate shells from the silicone molds and place in a muffin tin or other container to stabilize them.

For each bomb, combine 2 Tablespoons of hot cocoa powder with 1 oz. of Irish Whiskey (or your spirit of choice) until you have a paste. Add this mixture to 6 of the shells.
NOTE: If you're making non-alcoholic bombs, simply add 3 tablespoons of hot cocoa mix to the 6 shells and top with a handful of mini marshmallows.

Using a plastic baggie, pipe a fine line around the edge of one or both spheres. Place the top one on the bottom one filled with the paste (or marshmallows and mix), center to fit accurately, and if necessary, wipe extra chocolate from the rim with your forefinger. Or leave it and roll the sphere in decorative sprinkles.

This is a most important step, these balls have to be tightly sealed to avoid having the alcohol leak. I worried that I didn't love the look but honestly once you decorate them, you'll never notice a less than perfect seam; having it work is more important!

(For bombs without alcohol, you can place a plate over the pot of simmering water to heat it up a bit. Then press the rim of each of the empty half spheres to the plate to melt them a bit before filling them and then adhere the two together.

Wipe out and thoroughly dry your double boiler or use a new dish and melt the white chocolate chips. Fill a small plastic baggie with the melted chocolate and cut a TINY hole on one edge; drizzle the chocolate over each ball. Top with your favorite sprinkles. Refrigerate the completed balls.

To serve, place a ball into a cup and pour hot milk over it until the ball bursts open. Stir until smooth and top with marshmallows if desired.