Stir together the cake mix and pudding. Add the remaining ingredients and beat till well combined. Pour into prepared cake pans and bake for 30-40 minutes until it tests done.
Cream butter until smooth. With mixer on low, slowly add the powdered sugar. Add the heavy cream until it reaches spreading consistency. Add in mint extract and small amount of green food coloring. Stir in chocolate chips.
Place chocolate and heavy cream in microwavable bowl and microwave for one minute. Stir and then continue to microwave for 20 seconds at a time until it is smooth.