Turn your oven on to 200C / 400F / Gas mark 6. Line a baking tray with parchment paper and pour your sugar on to it and pop it in your oven to warm up.
Add your egg whites to your stand-mixer bowl and slowly at first start to whisk them. Once bubbles start to appear then turn up the speed on your mixer until you have reached stiff peak stage and it is thick and shinny about 5 minutes.
Turn your oven off and retrieve your sugar, it should be nicely warm at this stage.
Pour half of it into your beaten egg whites and whisk for a minute or two until the mixture feels smooth between your fingers.
Add your vanilla bean paste, cornflour (cornstarch) and white wine vinegar / lemon juice, whisk for a few seconds and then add your remaining sugar and whisk for a further 5 to 7 minutes until you have a stiff shinny smooth mixture. You are looking to have all the sugar dissolved into your egg whites. Rub a little of it between your fingers it should feel smooth and not grainy. If it is a little grainy whisk for another minute or two.
While the meringue is whisking turn your oven back on to 150C / 300F / Gas mark 2.
Using a large baking sheet lined with parchment paper, carefully pour your uncooked meringue into the centre of the baking sheet.
Using a rubber spatular or large pallet knife very gently spread it out in a circular motion so the pavlova is about the size of a dinner plate and about 1 to 1 and 1/2 inches thick. Also slightly dip it in the middle so the cream and fruit sit in the dip.
Pop it on the bottom shelf of your oven and leave it for 1 hour and 15 minutes. After this time check on it, it should be just off white and sound a little hollow if gently tapped and feel firm when touched. Another quick test is to try and lift the pavlova, it should easily come away from the parchment paper. If it doesn't then leave it for another 15 minutes and check again.
Once fully baked turn off the oven and leave the pavlova inside the oven for a further 30 minutes.
Once the time is up take it out of the oven and while it is fully cooling down make the frosting.