- For the cakes:
- 2 (15.25-ounce) boxes devil's food cake mix
- For the candy shell:
- 3 pounds royal blue candy melts (or desired M&M’s color)
- 2 tablespoons coconut oil
- For the interior:
- 1 cup plain M&M’s
- 4 ounces semisweet chocolate, melted
- For decoration:
- 4 ounces melted white chocolate candy melts
- Preheat oven to 350 degrees.
- In the bowl of a stand mixer, make both cake mixes according to the instructions. Divide batter between two 9x4-inch oven-safe glass bowls, and bake for 1 hour or until a toothpick inserted into the center comes out clean. Let cool for 10 minutes then turn out onto a rack and let cool completely.
- Fill a medium saucepan with 3 inches of water and bring to a slow simmer over medium-low heat. Place a heatproof bowl over the pan, making sure the water does not touch the bowl. Add 24 ounces of blue candy melts and 1 tablespoon of coconut oil to the bowl, stirring constantly until smooth. (Alternately, you can use a microwave in 30 second increments, stirring in between.)
- Using the clean glass bowls that the cakes were baked in, pour the candy melts into both. Using a spatula, spread the candy melts evenly until the melts cool and begin to harden. (By spreading the melts with a spatula, a uniform width in the candy shell can be achieved.) Place the candy shell into the freezer for 20 minutes.
- Cut 2 inches off the wider top of each bowl cake, and carve one 4x4-inch hole in the center of one of the bowls to form an internal bowl. Fill the internal bowl with melted chocolate and M&M's.
- Remove candy melt shells from the freezer and pop out of glass bowls. Place the cake with the chocolate indentation into a candy shell and top with the other cake.
- Pipe remaining blue chocolate around the edges of the candy shell and top with the other shell. Let chill in the refrigerator for 10 minutes. Carefully flip the dome when ready to serve and pipe a white chocolate “m” on top. Slice and serve!