My daughter asked for a chocolate peanut butter cake for her Elsa themed 3rd Birthday. I was so happy when I googled this and a Nigella recipe came up straight away! I feel Nigella recipes are fail safe and are always amazing! The cake was so simple to make but I doubled the recipe to get the extra height I needed. I was hoping for blue peanut butter frosting but because of the peanut butter colour it went slightly green but hey they mention the northern lights in frozen so I just rolled with it!! I got so many compliments when we cut the cake. It tasted amazing and everyone wanted to take some home. Nigella nails it once again!