Preheat oven to 300F. Mix the egg whites in your mixer on high speed until stiff peaks form. Slowly add 1/4 of a cup of sugar at a time. Once you added all the sugar, mix on high for another 2 minutes until the egg whites are thick.
In a small bowl, mix cornstarch, vinegar and vanilla extract well and then add to the egg white mixture. Mix in for 20 seconds to incorporate well.
Line a baking tray with parchment paper and scoop out the eggwhite mixture. Use a spatula or a spoon to shape the mixture into a round 8-inch nest like a circle. Reduce oven temperature to 250F and place your meringue on the middle shelf.
Cook for 1 hour and 15 minutes until it’s lightly browned. Leave the pavlova in the turned off oven with the door closed for 2 hours. Whip the cream, and once ready to serve top with whipped cream and fresh berries. Serve right away - the meringue will get soggy the longer it stays out when topped with the whipped cream.