For the cake:

• 1 orange and 2 clementines (or 2 oranges)
• 6 eggs
• 250 g (9 oz) caster (superfine) sugar
• 250 g (9 oz/2½ cups) almond meal
• 1 teaspoon baking powder Rose petals and/or shelled pistachios (optional)

For the icing:

• Grated zest and juice of 1 lemon
• 2 tablespoons sugar

MAKE THE CAKE. Fill a large saucepan with water and bring it to the boil on the stove, then add the fruit and poach for 2 hours in the gently simmering water. Add more water during this time if needed. Drain the fruit and let them cool, then chop roughly and remove any seeds or pith. Purée in a food processor.

PREHEAT THE OVEN TO 190°C (375°F/GAS 5). Break the eggs into a mixing bowl. Add the citrus puree, then the caster sugar, almond meal and baking powder. Mix together well and pour the batter into a round 22 cm (8½ inch) spring-form cake tin.

BAKE THE CAKE FOR ABOUT 1 HOUR. Test whether it is cooked by inserting the tip of a knife into the middle; if it comes out clean, the cake is cooked. Remove it from the oven and let it cool slightly.

MEANWHILE, MAKE THE ICING. Combine the lemon juice and zest with the sugar. Pour this mixture over the still-warm cake and let it dry so the icing forms a crust on top of the cake.

YOU CAN DECORATE THE CAKE WITH ROSE PETALS AND/OR PISTACHIOS.