Preheat oven to 180ºC and grease a loaf tin.
Beat eggs and sugar together with an electric beater until light, fluffy and doubled in volume. (This is very important and may take up to 6 minutes)
Mash/blend/beat avocado well so that it is smooth and silky.
Sift the flour and add together with the avocado. Fold through gently, scraping down the sides of the bowl to ensure none of the avocado goodness is left behind.
Pour into the loaf tin, even out the surface and bake in the oven for 40-45 minutes. Insert a skewer/knife into the centre and if it comes out clean, then the cake is done.
Allow to cool completely before taking out of the loaf tin and icing.For the icing:
Mix together the icing sugar, zest, juice and cream cheese until you have a firm but smooth icing.
Use a knife to smear onto the top of the cake and sprinkle over pistachios.
Recipe reprinted with permission of Undomestikated. To see more recipes, click here.