Method 
1. Preheat oven to 150°C (300°F).
2. Place the eggwhite in the bowl of an electric mixer and whisk until stiff peaks form. Gradually add the sugar, whisking well, until the mixture is stiff and glossy. Add the cornflour and vinegar and whisk until just combined. Shape the mixture into an 18cm round on a baking tray lined with non-stick baking paper.
3. Reduce oven to 120°C (250°F) and bake for 1 hour 20 minutes. Turn the oven off and allow the pavlova to cool completely in the oven.
4. Decorate with your desired toppings.
