Raspberry ripple roulade

Instructions

1. Preheat the oven to 160°C, fan 140°C, gas 4. Line a 33 x 23cm Swiss roll tin with baking paper. Beat the egg whites with an electric whisk until frothy and doubled in volume. Slowly whisk in the caster sugar until thick and shiny. Mix the cornflour, vinegar and vanilla extract together, then whisk this into the egg whites.
2. Spoon the mixture into the tin and level the surface. Bake for 25 minutes until the top of the meringue is just firm.
3. Meanwhile, make the raspberry purée. Put the berries in a pan with the sugar and lemon, lightly crush and cook for 5 minutes over a medium heat until starting to break down. Transfer to a mini food processor and purée into a sauce, then press through a sieve to remove any seeds. Let cool.
4. Remove the roulade from the oven. Dust a sheet of greaseproof paper with icing sugar and turn the meringue out onto the sugar dusted paper. Peel off the lining paper.
5. Make the filling. In a medium bowl, combine the yogurt and icing sugar, then stir in the vanilla. Spread the mixture over the meringue, leaving a 2cm strip along the long edge furthest away from you, and dot over the raspberry purée. Use a spoon to gently ripple the raspberry through the yogurt, then scatter over the whole raspberries.
6. Roll up the roulade, starting with the short end and using the paper underneath to help. Carefully transfer to a board and slice to serve.