Add chocolate chips to a microwave-safe bowl and microwave on 50% power for 60 seconds. Stir and repeat. Stir until melted completely.

Scoop 1 large dollop of chocolate into 3 of the molds. Drag the dollop on the bottom of the mold and up the sides to coat evenly. Freeze for 15 minutes. You will not use all the chocolate for the cavities. 

Remove mold from the freezer and check to make sure each cavity is coated in chocolate. 

Add 1 tablespoon of hot chocolate mix to each cavity and top with mini marshmallows, filling the mold. 

If necessary, reheat the remaining chocolate. Add it to the microwave and microwave at 50% power for 15-30 seconds and stir until smooth. Divide chocolate into thirds and add a dollop on the top of each cavity. Gently spread with the back of the spoon to seal shut. Freeze for 15 minutes or until chocolate is solid. 

Gently pull the mold away from the chocolate and press on the bottom, turning the mold inside out and removing the bomb.

Place bombs onto a piece of wax paper. Place white chocolate chips into a resealable sandwich bag and place into the microwave for 30 seconds at 50% power. Remove and knead until smooth. If necessary, return to the microwave in 10 second increments at 50% power until smooth. Snip the tip of the bag and drizzle on the bombs. Let stand to harden. 

Store bombs in a sealable plastic bag before using. 

To serve: Place into a mug and pour nearly boiling milk on top of the chocolate. Stir well until melted and combined.