Preheat your oven to 350°F (175°C). Line your cupcake pan with cupcake liners to prevent sticking and for easy cleanup.
In a large mixing bowl, whisk together the devil's food cake mix and the instant chocolate pudding mix until well combined.
To the dry mixture, add the sour cream, vegetable oil, beaten eggs, and pure vanilla extract. Mix on medium speed until well blended.
Gradually add the warm water to the mixture and continue to mix until smooth. The batter will be somewhat runny, which is perfect for moist cupcakes!
Gently fold in the Andes Crème de Menthe baking chips until evenly distributed throughout the batter.
Using a measuring cup or ice cream scoop, fill each cupcake liner about two-thirds full with batter.
Place the cupcake pan in the preheated oven and bake for 18-20 minutes, or until a toothpick inserted in the center comes out clean. Allow the cupcakes to cool in the pan for 5 minutes before transferring them to a wire rack to cool completely.
In a large mixing bowl, beat the room-temperature unsalted butter until creamy. Gradually add the sifted confectioners' sugar, mixing on low speed. Once combined, add the heavy cream, peppermint extract, and green gel dye (if using). Beat on high speed until the frosting is fluffy and light.
Once the cupcakes are completely cool, frost them generously with the mint buttercream. You can use a piping bag for a professional touch or simply spread it on with a spatula.
Drizzle the melted semi-sweet chocolate over the frosted cupcakes and sprinkle mini chocolate chips on top for an extra chocolatey crunch.
