Place the dark chocolate in a bowl and melt it in the microwave in 30-second rounds.
With a teaspoon, place the melted chocolate in the sphere silicon mold and make sure the whole sphere is coated.
Place the mold in the freezer for 3 minutes.
Take out the mold and create a second layer of chocolate for each sphere.
Place again in the freezer for 3 minutes to set.
Carefully release the spheres out of the mold, fill with 1 teaspoon of cocoa mixture and a few mini marshmallows.
Place some melted chocolate in a piping bag.
Pipe melted chocolate on the rim of one sphere and close with another sphere.
Drizzle more chocolate on the outside of the bomb for garnish and add the sprinkles on top.
Place the bomb in a mug.
Warm milk in a small pot or in a mug in the microwave.
Pour the milk on the bomb.
Watch the bomb open, stir well.
Have a sip and enjoy!