Preheat oven to 350°F/160°C. Bring water to boiling
Add all dry ingredients together in a large mixing bowl and stir. Add eggs, chocolate mint milk, oil, and vanilla. Blend for 2 minutes then combine hot water.
Lastly, stir in chocolate chips. Pour batter into lined cupcake cups.
Bake for about 20 minutes. Let cool. Remove cupcakes from pan and let cool completely.
To make cocoa buttercream frosting: beat softened butter and shortening in a stand mixer until fluffy. In a separate bowl combine cocoa and powdered sugar. Slowly add sugar mixture to the mixer while continuously beating. Then, add chocolate mint milk and beat until frosting is combined.
Lastly, frost cupcakes and top with crushed candy cane for garnish.