Brace yourselves – this cake is made with mayonnaise! But mayonnaise is made from eggs and oil so actually, not so weird? It is one of Lucy LT’s ‘wonder cakes’. She has been baking this for years and serving it cold as a cake, or warm with thick cream and thick toffee sauce as a pudding – oh yes! I don’t like bananas, so created the carrot and parsnip versions. We’ve used Hellmann’s mayonnaise as it has around 8 per cent egg content. Some other brands have less and, as in any cake recipe, the proportion of egg is important, so add a little extra mayo if it has less egg.