1

Preheat the oven to Gas Mark 5/190°C/375°F/fan oven 170°C. Spray a 20cm (8 inch) round loose-bottomed cake tin with low fat cooking spray and line the base with a circle of greaseproof paper.

2

In a large bowl, whisk the eggs, sugar and half the lemon and lime zest together using a hand-held electric mixer until very thick, light and airy. This will take about 5 minutes. Gently fold in the flour and salt using a large metal spoon. Transfer to the cake tin and level the surface.

3

Bake the cake for 10-12 minutes until firm, yet slightly springy to touch. Put the cake, in the tin, on a wire cooling rack.

4

Put the lemon and lime juice into a small saucepan with the remaining zest. Add the icing sugar and heat gently until dissolved. Bring to the boil, then immediately remove from the heat. Slowly spoon this syrup over the cake whilst the cake is still warm. Cool in the tin, then remove carefully. Serve when cold.