Coat the mold with glitter: Liberally coat the inside of each mold cavity with the edible glitter. The glitter will stick to the silicone. You don’t need to prep the mold in any special way.
Melt the candy melts: Place candy melts in a microwave-safe bowl and melt in the microwave, following the directions on the package.
Fill the mold: Place 1 tablespoon of the melted candy melts into one cavity of the bomb mold and, using the bottom of your tablespoon measuring spoon, press the chocolate up the sides of the mold, keeping it thick but even. Repeat the process with 12 bomb mold halves. Do not throw out your remaining melted chocolate (reserve it for a subsequent step).
Freeze: Place the chocolate-filled bomb molds into the freezer for 5 minutes. Remove molds from the freezer and gently pull the silicone mold away from the chocolate half-spheres.
Fix the edges: If the edges of your chocolate half-spheres are not even, heat a plate in the microwave until it is warm to the touch. Then turn each of the half-spheres open-side down onto the plate’s surface and gently melt the edge, making it even.
Fill the cocoa bombs: Fill 6 of the chocolate half-spheres with 1 tablespoon hot chocolate mix and 5-6 mini-marshmallows.
Close the chocolate bombs: Turn one of the half-spheres open-side down onto the plate’s surface and gently melt the edge. Immediately press this empty half-sphere to the top of one of the filled cups.
This will close the hot chocolate bomb. Alternatively, you can pipe a little of the melted candy melts along the edge of each filled half-sphere then place an empty half-sphere on top. Repeat with all of the hot chocolate bombs.
Freeze again: Place them into the freezer for 5 minutes to get them to set, then remove.
Decorate: If you don’t have premade antlers, place ½ of your reserved melted chocolate into a piping bag with a small piping tip (or a zipper top bag with a very small corner cut out) and pipe 1 ½-inch tall antler shapes onto a baking sheet lined with parchment paper. Place these in the freezer to set for 5 minutes. Remove from the freezer and peel off the parchment paper using a metal spatula.
With your reserved melted chocolate, dip the base of a reindeer antler into the chocolate, attaching a liberal bit of chocolate to the end of the antler. Immediately press this to one side of a hot cocoa bomb top.
Hold for a moment until the chocolate hardens enough to hold the antler steady. Repeat placing a second antler on the same cocoa bomb, then repeat until all of the hot cocoa bombs have two antlers. Again, do not discard your melted chocolate.
Place them into the freezer for 5 minutes to get the antlers to set, then remove.
Using the melted chocolate you reserved, add a dab to the back of a bow and place it on the head between the antlers or below the midline of the hot chocolate bomb for a bow tie. Repeat for all of them.
Add a dab of melted chocolate on the back of each candy eyeball and place it on the hot cocoa bomb, just above the midline of the bomb and to one side, below an antler. Repeat with a second eyeball so that the reindeer hot chocolate bomb has two eyes. Repeat for all of the cocoa bombs.
Add a dab of melted chocolate on the back of a black or red jelly bean and place it on the hot cocoa bomb, between the eyes and at the midline of the hot cocoa bomb. Repeat for all of the hot cocoa bombs.
Freeze to set: Place the hot cocoa bombs into the freezer for 5 minutes to get the decorations to set, then remove and store in an airtight container until you’re ready to use.
Serve and enjoy: To use the hot cocoa bombs, place them in a mug and pour hot milk over the top. Stir until the hot cocoa bombs are fully melted and enjoy!