Melt candy melts in a heat-safe container - I used a DIY double boiler involving a 2-cup and a 4-cup Pyrex container. (You can 100% do this in the microwave, but you may need to re-melt if you’re doing more than one set of shells. Also use caution; candy melts will seize (harden+crumble) if overheated.

Chill 5 minutes (or leave at room temp for 15-20 minutes) until hardened and set. Remove gently from molds. (Bend the silicone back and remove in a peeling motion so the shells don’t crack.)

Pour very hot (near-boiling) water into a heat-safe bowl, and place a heat-safe plate over the top. Wait 1-2 minutes for the plate to warm up.

Gently place a shell half edge-down onto the plate, and turn it until the edges are smooth and even. Repeat with half of the shells.

To each of the ‘smoothed’ shells add 1 Tablespoon of cocoa powder, as many marshmallows as will fit, and sprinkles if using.

Repeat the ‘smoothing’ process on each of the remaining shells - one at a time - and when a shell is smoothed + slightly melted adhere to a filled shell with gentle pressure. I used a bit of the leftover melted chocolate to help the shells adhere where there were any gaps.

Melt the white candy melts and transfer to a piping bag. Pipe a ‘+’ shape and then an ‘X’ shape onto a bomb, followed by a large circular ‘swirl’ shape to mimic a spider web.

De-mold skulls and adhere one to the top of each hot cocoa bomb.

Serve by placing into a glass and pouring hot milk over the top - I recommend placing them in sideways and aiming your ‘pour’ at the seam since it’ll melt and come apart the easiest. Looks more like an ‘bomb’ that way. Enjoy!