In a small, microwave safe bowl, melt 2 cups semisweet chocolate chips in 30 second increments, stirring in between. This should take 60 to 90 seconds. Alternatively, you can melt the chocolate in a double boiler on the stove.
Once melted, spoon about 2 tablespoons into each half sphere and using a pastry brush or the back of a spoon, spread the chocolate around the whole sphere making sure the edges are well coated so that they are not fragile.
Let the chocolate set in the fridge or freezer until hardened, about 10 minutes. Once set, gently remove from the molds.
Lay 6 half spheres on a plate, with the edges face down. In a small, microwave safe bowl, melt ¼ c semi sweet chocolate chips in 30 second increments, stirring in between. This should take 30 to 60 seconds.
Once melted, spoon into a baggie or piping bag. Snip a small corner in the bag. Drizzle one half sphere with melted chocolate. Place several mini, multicolored chocolate chips on top of the drizzle before it hardens. Repeat with 5 more half spheres.
Let set in the fridge or freezer for 3 to 5 minutes until hardened.
Lay the 6 remaining, plain half spheres face up on a plate. Spoon 1 tablespoon of the hot cocoa mix into each half sphere. Top with several mini marshmallows or other mix-ins.
Warm a small, microwave safe plate in the microwave for 45 to 60 seconds. Lay decorated, empty half sphere on the plate for a couple seconds until it begins to melt the edges. This creates an even edge and a sort of glue. Connect with the corresponding, filled half sphere so that the edges meet. Repeat with the remaining 5 spheres until they are all completed. Serve and enjoy!
To make hot cocoa - set hot cocoa ball in the bottom of a mug and pour 6 oz of hot milk or water over top until the shell has melted in, releasing the hot cocoa powder, cosmic brownie and mini marshmallows. Stir with a spoon until emulsified.