Mix flour, sugar, baking powder, baking soda, and cocoa powder.
Beat in oil and eggs, then mint extract, sour cream, and milk. If mixture is too dry, add ¼ cup more water.
Pour into a lined cupcake pan, up to a little over half full. Bake at 350 for 15-20 minutes or until cooked through. When cooked, fully cool.
To make white frosting: Beat together all ingredients. If it isn’t smooth enough, add 2 tablespoon milk. Set aside.
To make chocolate frosting: Heat heavy cream on medium on the stove top for 10 minutes.
Pour in a bowl of chocolate chips, let sit, and then whisk together until smooth.
Beat in sifted powdered sugar.
Combine white and chocolate frosting in a piping bag, and swirl onto cupcakes.
Sprinkle with crushed mints.