Add 14 oz of white chocolate to a medium bowl and microwave for 30 seconds. Remove from the microwave, and stir as much as you can. **
Continue to microwave in 15 second intervals, stirring fully and scraping the sides of the bowl with a rubber spatula between one, until the chocolate is almost completely melted.
Then continue to stir the white chocolate so that it's own heat continues to melt the un-melted pieces.
Once it is smooth, check the temperature with an instant read thermometer to make sure that the melted white chocolate reads between 82 and 84 degrees. If the temperature goes over 84 degrees, add in an additional ounce or two of chopped white chocolate to lower the temperature.
Spoon about 1 Tablespoon of melted chocolate into each of the hot chocolate molds.
Use the back of a small spoon to spread it around. Make sure to get the white chocolate all the way to the top of the rim, and to cover any exposed areas.
Place the mold on a small baking sheet and refrigerate for 5 minutes.
Remove the mold from the fridge and spoon another heaping spoonful of white chocolate into one half dome. Use the back of the spoon to work the second layer of white chocolate around, really building up the edges to make them thicker, to help them not to crack. Repeat with additional half domes.
Place the mold into the freezer to chill for 10 minutes.
Once all 12 shells are made, microwave a flat microwave safe plate for 2 minutes.
Place 6 of the shells on the plate, one at a time, and use your gloved hand to gently spin them on the plate, to smooth the edges.
Place the round side down in a regular cupcake liner to hold the hot cocoa bombs.
Fill the shells in the cupcake liners with about 1.25oz of white hot cocoa mix each. Then top with as many lucky charms marshmallows as you can.
Wipe the plate clean.
Reheat the plate for another 2 minutes in the microwave.
Then repeat the process with the remaining 6 shells, and place them on top of the filled halves. Gently press them down to seal them together.
Let the hot chocolate bombs set for a few minutes.
Drizzle extra melted white chocolate over the top of the cocoa bombs, and top with sprinkles if desired.