Place the milk chocolate morsels into a microwave-safe bowl and heat in the microwave about 2 minutes, stirring every 15 seconds, until completely melted. Repeat the same process with the white chocolate.
Add a heaping tablespoon of melted chocolate into molds. Spread using the back of the spoon until each cavity is completely covered.
Place in the refrigerator and let set for about 15 minutes.
Remove molds from refrigerator, and press gently on the top of each sphere to carefully remove onto a baking sheet.
Fill 6 spheres with a tablespoon of hot chocolate mix and couple of tablespoons of mini marshmallows, each.
Warm a skillet or plate, and place the bottom of an empty sphere on the plate to lightly melt chocolate. Place melted chocolate edge on top of the filled half to seal.
Optional: Decorate the hot chocolate bombs by drizzling a little melted chocolate on top of each bomb.
Refrigerate until ready to serve.
Enjoy!