Watermelon, berry and white chocolate pavlova

Method

1. Heat the oven to 200°C/180°C fan/gas 6. Draw a 25cm diameter circle on the sheet of non-stick baking paper with a pencil. Whisk the egg whites in a large, clean mixing bowl using an electric mixer until stiff peaks form when the beaters are lifted (3-4 minutes).
2. Gradually add the caster sugar, 1 tbsp at a time, whisking well after each addition and bringing the whites back to stiff peaks before you add more sugar. Once you’ve whisked in half the sugar, add the rest in larger quantities. When all the sugar has been added, whisk the meringue back to glossy, stiff peaks, then whisk in the cream of tartar, vinegar and cornflour.
3. Dab 4 tiny dots of meringue onto the corners of a baking sheet, then cover with the baking paper (pencil-side down). Spoon the remaining meringue into the circle and use the back of a spoon to make pillowy swirls. Transfer to the oven and reduce the temperature to 130°C/110°C fan/gas ¾. Cook for 1½ hours, then turn off the oven (don’t open the door) and leave to cool completely for 4-5 hours. Remove the meringue, carefully peel off the paper, then put on a serving plate/cake stand.
4. Brush the inside of the cooled pavlova with the melted white chocolate (see tip) and leave to set completely.
5. Put 100g of the strawberries and 50g of the raspberries in the small bowl of a food processor with the icing sugar and lemon juice. Whizz until smooth, then strain into a bowl (discard the seeds). Quarter the rest of the strawberries and add to the bowl with the remaining raspberries, watermelon chunks and shredded mint.
6. For the filling, mix together the yogurt and double cream, then sweeten to taste with the icing sugar. Top the pavlova with spoonfuls of the yogurt cream, then spoon over the fruit mixture, scatter over a few mint leaves and the freeze-dried berries.