In a small bowl, combine the powdered sugar, cocoa powder, chopped white chocolate, and mini marshmallows. Set aside until ready to use.
Melt the white chocolate bark according to the package directions.
Add 2 tablespoons of melted white chocolate to each well of a silicone chocolate mold. Don’t throw away any extra chocolate - we will use it later!
Use a spoon or pastry brush to paint the chocolate evenly over each mold. Make sure to have a thick layer of chocolate so you don’t end up with brittle hot chocolate bombs.
Once each well has a thick layer of chocolate, transfer the mold to the fridge and allow it to chill until set, about 10 minutes.
Once the chocolate has set, carefully remove each piece from the mold. It should look like a small bowl! I like to use gloves when I handle the chocolate so I don’t leave fingerprints on it!
Fill half of the chocolate bowls with hot chocolate powder (about 2 tablespoons per bowl).
Heat a small skillet over medium heat just until warm. Place one chocolate bowl open side down onto the warm skillet for 1-2 seconds, or just until the edges start to melt.
Then place the bowl on top of one of the filled chocolate bowls and press them together gently to seal.
Repeat steps 8 and 9 with the remaining chocolates.
Remelt any of your remaining chocolate bark. Transfer it to a plastic bag and cut a small piece off the corner. Drizzle the chocolate over the filled hot chocolate bombs and attach two candy eyes on top, just make sure to put on the candy eyes while the drizzle is still wet.
Allow the chocolate to fully set before serving. Store in an airtight container in the fridge for up to one week.