These whoopie pies are soft, airy chocolate sponge cakes with a layer of mint choc chip filling. They also happen to fit in with both St Patrick's day and Pi Day. Mint Choc Whoopie Pies Author: Harry Jennerway Prep time: 15 mins Cook time: 10 mins Total time: 25 mins Serves: 6 Ingredients Whoopie Pies