1. Reserve 12 M&M's Holiday Mint; set aside.
2. In microwavable bowl, melt dark chocolate, stirring every 30 seconds, for 2 to 3 minutes or until chocolate is melted.
3. Place 24 (2 1/2-inch) half sphere molds on baking tray. Spoon 1/2 tbsp melted dark chocolate into cavity of each mold; brush to coat cavity evenly. Repeat with remaining molds. Refrigerate baking tray for 15 to 20 minutes or until chocolate is set.
4. One at a time, remove empty shells from mold. Transfer to parchment paper-lined baking tray. 
5. Add 1 tbsp hot chocolate powder, 1 tbsp mini marshmallows and 1/2 tbsp of the remaining M&M's Holiday Mint to each of the 12 chocolate sphere halves. 
6. Heat small nonstick skillet over medium-low heat for 1 to 2 minutes or until warmed. Remove from heat. Place empty shell, open side down, on warm pan to heat edge. When edge begins to melt, remove from pan and press to cover 1 filled sheet. Hold for 30 seconds to seal. Repeat process with remaining shells. 
7. Place 2 oz of white chocolate in each of 2 microwabable bowls; microwave each bowl, stirring every 30 seconds, for 30 to 90 seconds or until chocolate is melted. Stir 1/2 tsp coconut oil into each bowl. 
8.  Add 4 to 6 drops of green food coloring to one of the melted white chocolate bowls; repeat with red food coloring. Stir until chocolate is evenly colored, adding more food coloring if needed for desired hues. Transfer to 2 separate resealable plastic bags; cut off tip from bottom corner. 
9. Drizzle green and red chocolate over each chocolate bomb; decorate each bomb with 1 reserved M&M's Holiday Mint in center. Refrigerate for 3 to 5 minutes or until chocolate drizzle is set. 

Tip: To serve, drop hot chocolate bomb into a mug; pour in boiling water or steamed milk. Stir to dissolve.