- 150g unsalted butter, softened
- 200g castor sugar
- 4 large eggs
- 225g ground almonds
- 2tsp baking powder
- 250g cold mashed potato
- finely grated zest 2 lemons and juice 1
- icing sugar, to dust
- For the syrup
- juice 2 lemons and zest 1
- 5tbsp castor sugar
- You will need
- 23cm round springform tin, buttered, and the base lined with baking paper
- Heat the oven to 180°C, 160°C fan. To make the cake, whisk together the butter and sugar until pale and fluffy. Gradually beat in the eggs, adding 1tbsp ground almonds to prevent curdling between additions. Now fold in the baking powder and remaining ground almonds. Gently fold in the mashed potato, lemon zest and juice, then pour into the prepared tin and level the top. Place the tin on a baking sheet in the centre of the oven and cook for 35 to 45 minutes; the mix will still be slightly sticky.
- Meanwhile, make the syrup: place the lemon juice and zest, and caster sugar in a small pan and simmer gently for 1 minute.
- Remove the cake from the oven, prick the surface all over with a skewer and spoon over the hot syrup until it's all absorbed. Cool in the tin for 1 hour before turning out to cool completely. Dust with icing sugar to serve, perhaps with a dollop of crème fraîche.