Prep the mold: Make sure the silicone mold is clean, dry, and free of lint. A quick polish with a paper towel helps the chocolate shine.

Melt the chocolate: Microwave method: Heat chopped chocolate in 20–30 second bursts, stirring between each until smooth. Stop when nearly melted; the residual heat will finish the job.

Double boiler method: Set a heatproof bowl over simmering water, stirring until smooth. Keep water from touching the bowl.

First coat: Spoon a tablespoon of chocolate into each cavity. Use the back of the spoon or a brush to push chocolate up the sides, building an even layer. Chill for 5–7 minutes until just set.

Second coat: Add another thin layer to cover any thin spots, especially the rims. This prevents cracks and leaks. Chill again until firm.

Unmold carefully: Gently peel the mold away from the chocolate, pushing from the bottom. Wear gloves to avoid fingerprints and melting. Place half-spheres on a cool plate.

Warm a plate or pan: Heat a plate in the microwave for 45–60 seconds, or warm a skillet on low. You’ll use this to level the edges.

Level the edges: Press the rim of an empty half-sphere against the warm surface for 2–3 seconds to melt it slightly and create a flat edge. Do this to all halves. Work quickly so they don’t soften too much.

Fill the bombs: In half of the shells, add about 1 tablespoon hot cocoa mix and a small handful of marshmallows. Add extras like peppermint or toffee if you like, but don’t overfill.

Seal the bombs: Take an empty half-sphere, warm its rim again briefly, then place it on top of a filled half to seal. Hold gently for a few seconds. Repeat for all.

Clean and decorate: If needed, smooth seams with a fingertip or a little melted chocolate. Drizzle with contrasting chocolate and add sprinkles. Let set at room temperature or chill for 5 minutes.

Serve: Heat milk until steaming (not boiling). Place a bomb in a mug and pour 8–10 oz hot milk over it. Stir and enjoy.