Grapefruit and poppy seed angel cake

Heat the oven to 180C/fan 160C/gas 4. Sift the flour with the caster sugar and cornflour, and stir through the poppy seeds and put to one side.

Whisk the egg whites with the cream of tartar, salt, grapefruit juice and zest until foamy using an electric whisk. Gradually add the icing sugar a spoonful at a time, whisking until firm peaks form. Add the flour mixture in 2 batches, using a large metal spoon to fold it in gently to retain the air, making sure there are no pockets of flour. Put the mixture into a clean, dry 25cm × 10cm angel cake tin and level out with the back of a spoon (it’s important not to butter the tin). Bake for 45-50 minutes or until a skewer comes out clean and the cake springs back when lightly pressed.

Remove from the oven turn the tin upside down and leave to cool in the tin for 1 hour.

Meanwhile, make the sugared peel by peeling the remaining grapefruit with a swivel peeler, leaving the white pith behind. Cut the strips into fine matchsticks, boil in water for 5 minutes and drain.

Put the peel back into the empty pan. Juice the grapefruit and add 150ml to the saucepan with the sugar. Dissolve the sugar over a gentle heat before boiling the peel for 5-7 minutes until the peel is candied. Remove the peel with a slotted spoon, separate out on some baking parchment and cool. Toss the peel with the sugar to coat and leave to dry.

To remove the cake, run a palette knife around the inner and outer edges of the tin until the cake comes away. Remove from the tin and put bottom-side up on a cake stand.

For the icing, melt the white chocolate, cream and icing sugar in a saucepan over a low heat, stirring until just melted. Spoon on top of the cake while still warm, working quickly as it will start to set. Top with the sugared peel to serve.