Steam the potatoes in the microwave until soft. Wrap each one individually in cling-film and heat at 700 W for about 6 minutes, turing over halfway through.
Combine the steamed potatoes and the rest of ingredients and use a stick mixer or food processor to blend.
I used the deep container that came with my stick mixer. Once the batter reaches a thick and creamy consistency, it's done.
Line the cake pan with parchment paper and bake the cake at 180°C for about 35 minutes. Once it has cooled completely, remove from the pan.
The cake will only brown slightly, even when it's cooked through. Wait for it to cool before cutting.
Story Behind this Recipe
Every year, my parents send me loads of potatoes from their garden. If I try to use them up just in meals, I get stuck in a pattern of making the same thing over and over again. I was always wondering if there were any desserts that I could make with potatoes. I finally came up with this recipe after a lot of trial and error.
The most important thing is to get the batter smooth and creamy! If you don't have a food processor or a mixer, be sure to pass the batter through a sieve. I recommend chilling the cake in the fridge before eating. Also, if you add 4 g of powdered kanten, it will be firm when chilled.