01 -
Preheat oven to 300°F (148°C). Prepare three 8-inch cake pans with parchment paper circles in the bottom, and grease the sides.
02 -
Add flour, sugar, cocoa powder, baking soda, and salt to a large bowl and whisk together.
03 -
Add the eggs, milk, and vegetable oil to the dry ingredients and mix until well combined.
04 -
Add vanilla to the hot water, then pour into the batter. Mix until well combined. The batter will be very thin.
05 -
Divide batter evenly between cake pans and bake for 30–33 minutes, or until a toothpick comes out with a few crumbs.
06 -
Remove cakes from the oven and cool for about 10 minutes before transferring to cooling racks.
07 -
Beat butter in a mixing bowl until smooth. Add half of the powdered sugar and mix until smooth. Add 3 tablespoons of heavy cream, vanilla extract, and mint extract, and mix until combined. Add remaining powdered sugar and mix until smooth. Adjust heaviness with more cream and add the gel icing color.
08 -
Sift finely chopped chocolate pieces to remove any powdery bits, then fold into the buttercream.
09 -
Trim cake domes from cooled cakes with a serrated knife. Place the first layer on a cake plate, spread 1 cup of buttercream evenly on top, then repeat for the second layer. Frost the exterior of the cake with the remaining buttercream.
10 -
Heat heavy whipping cream until boiling. Pour over chocolate chips in a bowl and let sit for 2–3 minutes. Whisk until smooth.
11 -
Drizzle ganache around the cake edges and spread the remainder on top. Pipe frosting around the top edge of the cake and garnish with chopped chocolate.
12 -
Keep the cake in an airtight carrier or well covered at room temperature for up to 24 hours, and then refrigerate.