Preheat oven to 150°C and line a baking tray with parchment paper.
Using an electric mixer, beat egg whites until soft peaks form.
Gradually add the sugar, beating well until the mixture is glossy and the sugar has dissolved.
Add the cornflour and vinegar and fold through.
Transfer mixture to piping bag with a nozzle attached and pipe round nest shapes around 10cm in diameter onto the parchment paper.
Place in the oven, reduce the heat to 120°C and cook for 20 minutes.
Then turn the oven off and allow the meringues to completely cool in the oven.