Top this classic carrot cake with carrot cake mix icing and chopped walnuts or pecans. Serve as a sweet treat with a cup of tea any time of the day.
Oil and line the base and sides of two 20cm cake tins with baking parchment. Whisk the oil, yogurt, eggs, vanilla and zest in a jug. Mix the flour, sugar, cinnamon and nutmeg with a good pinch of salt in a bowl. Add the wet ingredients to the dry, along with the carrots, raisins and half the nuts, if using. Mix well to combine, then divide between the tins. Bake for 25-30 mins or until a skewer inserted into the centre of the cake comes out clean.
If any wet mixture clings to the skewer, return to the oven for 5 mins, then check again. Leave to cool in the tins. To make the icing, beat the butter and sugar together until smooth. Remove the cakes from the tins and sandwich together with half the icing. Top with the remaining icing and scatter with the remaining walnuts.