Fearnley-Whittingstall says, "The idea for this lovely, moist cake came from Elena Wong on our production team. It's best made with leftover whole potatoes, which you’ve mashed or, even better, riced once cold." (Just make sure that if you're using leftovers, they don't contain too much butter, milk, or other seasonings!)
Have you ever made a cake with mashed potatoes?
• Get the recipe: Tim's Lemon Trickle Mash Cake