Preheat oven to 120 degrees celcius. Beat egg whites till soft peak forms, add sugar gradually and beat. Add vinegar and cornflour and mix. Place mixture into a rectangular baking tray lined with baking paper and bake in the oven for 15- 20 mins or untill brown on top. Cool in oven with door ajar. Turn onto another piece of baking paper, line with whipped cream and strawberries and roll long ways. Dust with icing sugar.