Ingredients

Step by step

1. First make the clementine curd. Beat the eggs and egg yolk together in a bowl with a fork, then beat in the clementine and lemon juice. Strain the mixture into a heatproof bowl and add the zests, sugar, butter and cornflour. Rest the bowl over a pan of gently simmering water and cook gently, stirring frequently, for 15-20 minutes until thick. Take care not to let the mixture get too hot or to let the bowl touch the water. You should be able to leave a trail on the surface when you drizzle it from the spoon or spatula. Transfer to another bowl (to prevent overcooking), stir in the Cointreau and leave to cool, then cover with clingfilm to prevent a skin forming. Chill until needed.
2. For the roulade, preheat the oven to 160°C, fan 140°C, gas 3. Lightly oil and line a 23cm x 33cm Swiss roll tin with nonstick baking paper.
3. Whisk the egg whites into stiff peaks in a large clean bowl. Gradually whisk in the 275g caster sugar, 1 tablespoon at a time, to make a stiff and glossy meringue. Whisk in the cornflour and vinegar, plus a small pinch of salt. Spread the mixture evenly in the prepared tin and bake for 25 minutes, until the surface of the meringue is lightly browned. (It will puff up a lot but don't worry, it will go down again as it cools.)
4. Lay a large sheet of nonstick baking paper onto the work surface and sprinkle it lightly with the rest of the caster sugar. Lift the warm meringue out of its tray and ease the paper away from the sides of the meringue, but don't peel it off completely. Using the edges of the paper, flip the meringue over onto the sugar-dusted paper and leave to go cold.
5. Whip the cream to soft but stable peaks. To fill the roulade, carefully peel off the lining paper from the meringue and spread it with the clementine curd. Go right up to the edges on 3 sides, but only to within 2.5cm of the longer edge furthest away from you. Spread the cream over the curd.
6. Starting with the long edge closest to you, and using the edge of the paper to help you, roll up the meringue as you would a Swiss roll. Leave the roulade wrapped in its paper, carefully lift onto a large clean baking sheet, and chill for at least 3 hours to hold it in shape.
7. To serve, melt the white chocolate in a heatproof bowl set over a pan of gently simmering water, making sure it doesn't touch the water. Stir until smooth. Unwrap the roulade, dust it with icing sugar and carefully transfer it to a flat serving plate. Drizzle with the melted white chocolate and scatter with golden sprinkles. Serve cut into slices.