Dark Chocolate Cupcakes with a Smooth and Fluffy Peanut Butter Frosting. These cupcakes are rich and moist with a light fluffy texture and are made using the same type of method used for making brownies. To make the swirls of icing, use a 1M icing tip. I just love the look that it gives the cupcakes. It reminds me of a soft serve ice cream cone.