Preheat the oven to 150°C/300°F/Gas Mark 2. Line two baking trays with baking parchment. Draw a large circle 25cm/10inch on each piece of parchment paper.
Place the icing sugar and egg whites in a standing food mixer and whisk on high for 10 minutes until glossy white peaks form. Using a spatula, gently fold in the cornflour and the white wine vinegar.
Divide the meringue mixture between the two baking trays and using a tablespoon, form two large meringue discs. Bake for 45 minutes, remove from the oven and allow to cool completely.
