- 525g blackberries
- 225g caster sugar
- 65ml water
- 3 large egg whites
- ¾ tsp white wine vinegar
- 1 tsp cornflour
- 50g icing sugar
- 300ml double cream
- 1 tsp vanilla-bean paste
- In a small pot, mix 225g blackberries, 50g caster sugar and 50ml water. Bring to the boil; simmer for 5 minutes until berries are soft. Blend until smooth; strain through a sieve into a bowl. (Discard seeds.) Cool.
- Preheat oven to 180 °C. Line a 23 x 33 cm swiss roll tin with baking paper, so paper is 5cm above the top of tin.
- In a grease-free bowl, beat egg whites to stiff peaks with a handheld electric whisk. Beat in remaining 175g caster sugar gradually, whisking to stiff peaks after each addition. Quickly beat in vinegar and cornflour. Spread into tin, smoothing to level.
- Set aside 75g fruit puree. Dollop the rest over meringue. With a knife, swirl through.
- Bake for 15 to 18 minutes until puffed and set. Cool for 10 minutes in tin. (Meringue will sink.) Using baking paper, lift out of tin onto a wire rack to cool completely.
- Lay baking paper on a work surface; invert meringue onto it. Peel away lining paper.
- In a medium bowl, whisk icing sugar, cream and vanilla to soft peaks. Spread over meringue. Lightly mash rest of berries; dot over cream. Using a knife, score a line (not all the way through) about 1,5cm in from one of the short sides of meringue. Using baking paper, roll up roulade, using the line to help begin the roll. Transfer to a serving plate. Mix 1 tbsp water into reserved puree; serve with the roulade