In a large bowl, use a whisk to combine the malted milk powder, sugar, cocoa powder, and salt.

Fill a medium pot almost halfway with water. Bring the water to a simmer over low heat.

Place a heat-safe bowl (glass or stainless steel) that can just fit on top of the pot of simmering water, but leaves a gap between the water and bottom of the bowl.

Add the white chocolate chips to the bowl. Keep the heat on low and use a rubber spatula to stir the melting chocolate chips until smooth. Remove the bowl of chocolate, but leave the water in the pot to be used later.

Line a baking sheet with parchment paper. Top with a wire rack.

Add a heaping spoonful of the melted chocolate to each of the six chocolate molds. Use the spoon to spread the chocolate up the sides of each mold. Make sure the entire inside of each mold is evenly coated with chocolate.

Flip the mold over onto the rack that is on top of the parchment-lined baking sheet. This will allow any excess chocolate to drip onto the parchment to be re-melted and used later if needed.

Place the molds in the refrigerator to chill for 20-25 minutes, or until set. You could also place the molds in the freezer for 10 minutes. While the molds are setting, line another baking sheet with parchment paper.

Once set, carefully remove the chocolate cups from the mold, placing them on the lined baking sheet.

In a medium skillet over low heat, gently press the edges of the chocolate half onto the warm surface. Press just long enough to smooth out all edges. Set back onto the baking sheet. (I like to wear gloves during this process to prevent any fingerprints.) Repeat this two more times, so that you will have three chocolate halves total to be filled.

Fill each of the three halves with 1 tablespoon of the chocolate milk powder and 1 tablespoon of mini marshmallows.

Working one at a time with the remaining three molds, repeat the process of slightly melting the rims of the molds.

Cover each filled chocolate half with an empty half, sealing it.

Decorate with any extra melted chocolate, sprinkles, and other candies. Use immediately, or within 24 hours, for best results. Store at room temperature.

To make hot chocolate, add a chocolate bomb into a mug. Slowly pour about 1½ cups of hot milk over the bombs and stir. Sip and enjoy!