Melt the dark chocolate chips in a microwave-safe bowl in 30 second bursts, stirring each time, until melted and smooth.
Fill a 6 hole chocolate half sphere mold with a tbsp of melted chocolate. Use a spoon to spread it evenly and make sure to spread the chocolate all the way up to the top of each cavity. Place in the freezer for 10 minutes to set.
Repeat with another layer of chocolate and freeze for another 10 minutes.
Remove from the freezer and carefully remove the chocolate spheres from the mold. Place it on a plate and store in the fridge.
Repeat with remaining chocolate to make another 6 half spheres.
While the chocolate is setting heat the baileys in a microwave-safe jug until hot. Pour it over the milk chocolate chips.
Stir until all chocolate is melted and smooth. Whisk through the protein powder or cocoa powder if using.
Place the chocolate ganache into the fridge for 10-15 minutes to set a little firmer.
Take the set chocolate molds and fill 6 half spheres with the baileys ganache.
Heat a small plate in the microwave.
Take one empty chocolate sphere and place the rim onto the heated plate to slightly melt the edges.
Place the sphere on top of a filled sphere and allow the melted chocolate to set.
Repeat with remaining spheres. Chill in the fridge for 10 minutes to set completely.
Pop the chocolate bombs out of the silicone mold and place on a baking sheet. If using, melt the white chocolate in the microwave and drizzle over the chocolate balls.
To serve heat 1 cup of milk, place a chocolate bomb into a mug and pour the hot milk over top to melt. Stir to combine.
Serve hot chocolate topped with whipped cream and a sprinkle of cocoa powder if desired.
Store chocolate bombs in an airtight container in the fridge for up to 1 week.