Bolo Polana

Ingredients

• 400 g floury potatoes, peeled
• 250 g raw cashew nuts
• 200 g butter, softened
• 250 g caster sugar
• 6 eggs, separated
• zest of 2 lemons
• zest of 1 orange
• 1 tsp vanilla extract
• 1/2 tsp fine salt
• 2 tbsp icing sugar
• extra butter and ground cashew, for the tin

Before you cook

• Line the base of a 23 cm springform tin, butter the sides and dust them with ground cashew
• Peel the potatoes and cut them into even chunks
• Separate the eggs into two clean bowls
• Zest the lemons and orange

Steps

1. Heat the oven to 180C.
2. Boil the potatoes in salted water for twenty minutes, until a knife slides in without resistance.
3. Drain the potatoes and leave them in the colander for five minutes to steam dry.
4. Push the potatoes through a ricer or mash them completely smooth, then set them aside to cool.
5. Grind the cashews in a food processor in short pulses until they are the texture of coarse sand, stopping before they turn to paste.
6. Beat the softened butter with the caster sugar for four minutes, until pale and light.
7. Beat in the egg yolks one at a time.
8. Fold in the cooled mashed potato, the ground cashews, both zests, the vanilla and the salt.
9. Whisk the egg whites in a clean bowl to firm peaks.
10. Fold a third of the whites into the heavy batter to loosen it.
11. Fold in the rest of the whites in two more additions, keeping as much air in as you can.
12. Scrape the batter into the tin and level the surface.
13. Bake for fifty-five to sixty-five minutes, until deep gold and a skewer comes out with a few damp crumbs.
14. Cool the cake in its tin for twenty minutes, then release the ring and dust the top with icing sugar.