Recipe adapted from To Life! Healthy Jewish Food by Judi Rose & Dr Jackie Rose. Photographs by Marc Gerstein for The Judi Rose Cookery Studio

Method

• Preheat oven to 180°C. Grease and line the base and sides of a 20cm spring-form or loose-bottomed cake tin with baking paper.
• Put the egg whites and salt in a medium bowl and the yolks in a larger one. With an electric beater, whisk the whites for 2-3 minutes until they hold stiff peaks then add 1 teaspoon of the sugar and whisk until glossy.
• Whisk the yolks with the remaining sugar for a couple of minutes until pale and smooth – the mixture should fall from the beaters in a ribbon.
• Zest and juice the lemon and the 2 oranges. Add the zest, 1 tablespoon of the lemon juice and 4 tablespoons of the orange juice to the yolk mixture (reserve the rest of the juice). Using a rubber spatula, fold in the oil, ground almonds, polenta and herbs.
• Stir a quarter of the beaten egg white into the polenta mixture to lighten the texture, then gently fold in the remaining whites until even, preserving as much air as you can. Gently coax the mixture into the prepared tin and smooth the top level.
• Bake for 25-30 minutes or until golden and springy to gentle touch. While still warm, prick the cake all over with a fork, then pour over the reserved orange and lemon juice.
• Leave for 10-15 minutes for the sponge to absorb the juice, then run a knife round the edge and release the cake from the tin.
• Not more than an hour before serving, peel and thinly slice the oranges and arrange on top of the cake. Serve plain or with Greek yoghurt.