Set your oven to 300°F (150°C). Line a baking sheet with parchment paper.
In a clean, dry bowl, beat the egg whites on medium speed until soft peaks form.
While continuously whisking, gradually add the sugar, a tablespoon at a time. Continue whisking until the mixture is glossy and has stiff peaks.
Gently fold in the vanilla extract, white vinegar, and cornstarch, ensuring you don't deflate the egg whites.
Using a spoon or piping bag, place mounds of the mixture onto the prepared baking sheet. You should aim for around 6-8 mounds, depending on your desired size. Create a well in the center of each mound using the back of a spoon. This will hold the cream and fruit later on.
Place the baking sheet in the oven and immediately reduce the temperature to 250°F (120°C). Bake for about 50-60 minutes, or until the pavlovas are dry to the touch and can be easily lifted off the parchment paper.
Once done, turn off the oven and leave the pavlovas inside with the door slightly ajar to cool slowly. This prevents cracking.
Just before serving, fill the center of each pavlova with whipped cream and top with your choice of fresh fruit.