Preheat oven to 180 degrees ( Celcius ). Using an electric mixer, beat the egg whites and sugar for 10 minutes or until thick and glossy. Mix vinegar, vanilla and cornflower together. Add to meringue. Beat on high speed for a further 5 minutes. Line an oven tray with baking paper. Draw a 22cm cirlce on the baking paper. Spread the mixture to within 2cm of the edge of the circle, keeping the same shape as round and even as possible.Smooth top surface over. Place Pavlova in oven then turn even temp down to 100 degrees ( C ). Bake Pavlova for one hour. Turn oven OFF. Open oven door very slightly and leave Pavlova in oven until cold. Carefully lift Pavlova onto a serving plate. Decorate with whipped cream and various fruit.