Place the candy melts into a microwave safe bowl and microwave according to package.
Place the molds onto a small baking sheet. Spoon a little of the melted candy into the mold.
Use back of spoon to spread candy around sides of mold. It's okay if some of the chocolate goes over the edge of the mold.
Once the molds are completely filled, place them in the freezer for 5 minutes, or until completely solid.
To loosen candy shell from mold, grab each end and give mold a tug. Gently pop out one of the shell halves.
Microwave a small plate just until it's warm to the touch (about 35 seconds for me). Place the open side of the shell half onto the plate and move it gently around the surface until the edge is smooth.
Spoon a little hot chocolate mix into shell. Then, top with mini marshmallows and a Cadbury Mini Egg.
Grab another shell half, warm it on the plate to create a smooth edge, and place on top of the filled shell.
Use extra melted candy to seal the seam of the cocoa bomb.
Then, add a little melted candy to the back of the icing decorations and set into place on the cocoa bomb.
Place the finished cocoa bomb in an Easter cupcake liner and freeze again for 5 minutes.
Repeat with the rest of the candy shell halves until all of the cocoa bombs are made.
Store hot cocoa bombs in a sealed container in the fridge or freezer until ready to use or gift.