Preheat your oven to 350°F (175°C) and spray three 8-inch round cake pans with nonstick spray. Line with parchment paper.

In a large bowl, combine flour, cocoa powder, sugar, baking powder, baking soda, and salt. Whisk until well blended.

In another bowl, whisk together oil, vanilla, eggs, and buttermilk. Gradually stir in hot water.

Combine wet and dry ingredients gently until just mixed. Divide batter evenly in prepared pans and spread out evenly.

Bake for 24 to 27 minutes, checking with a toothpick for doneness. Remove and cool for 10 minutes before transferring to a wire rack.

Beat butter until fluffy, then gradually add powdered sugar. Mix in peppermint extract, salt, and heavy cream. Fold in chopped chocolate.

Add food dye until the desired color is achieved, mixing carefully.

Layer the first cake on a serving plate and spread frosting, then sprinkle half of the Andes mints. Repeat with the second layer.

Add the third layer upside down for a flat top. Apply a crumb coat and refrigerate for 10 minutes.

Finish with a thicker frosting coat, creating a smooth effect, then decorate with additional Andes mints.