Preheat your oven to 225°F (110°C). Line a baking sheet with parchment paper and set it aside.
In a clean mixing bowl, add the room temperature egg whites. Using an electric mixer, beat the egg whites on medium speed until they become frothy.
Once frothy, gradually add the granulated sugar, one tablespoon at a time, while continuing to beat the egg whites. Beat until the mixture is glossy and stiff peaks form.
Gently fold in the white vinegar, vanilla extract, and cornstarch using a spatula. Be careful not to deflate the meringue.
Using a spoon or a piping bag, dollop or pipe the meringue onto the prepared baking sheet, forming small nests with a slight dip in the center for the filling.
Bake the pavlovas in the preheated oven for about 1 hour and 15 minutes, or until they are dry to the touch and can be easily lifted off the parchment paper.
Turn off the oven and leave the pavlovas inside with the door slightly ajar for an additional hour to cool completely. This helps prevent cracking.
Once cool, gently remove the pavlovas from the parchment paper. Fill each nest with whipped cream and top with your choice of fresh fruit.