Preheat your oven to 350°F (175°C). Grease and flour two 9-inch round cake pans.

In a large bowl, combine flour, granulated sugar, cocoa powder, baking powder, baking soda, and salt.

Add eggs, milk, vegetable oil, and vanilla extract. Beat on medium speed for 2 minutes.

Stir in boiling water until well combined. The batter will be thin.

Fold in mint chocolate chips.

Pour batter evenly into prepared pans. Bake for 30-35 minutes, or until a toothpick comes out clean.

Allow cakes to cool in pans for 10 minutes, then remove from pans and cool completely on wire racks.

For the frosting, beat softened butter until creamy.

Gradually add powdered sugar and peppermint extract, mixing well. Add a little heavy cream if needed for spreading consistency.

Once cakes are completely cooled, place one layer on a serving plate. Spread frosting on top, then place the second layer on top.

For the ganache, melt chocolate chips with heavy cream over low heat until smooth.

Pour over the top of the cake and let it drip down the sides.