Preheat the oven to 350°F Line a large baking sheet with parchment paper.
With a stand mixer, beat the egg whites on high speed until soft peaks form.
Add the sugar slolwy. Once all of the sugar has been added, turn the mixer up to high speed and continue beating until glossy stiff peaks form and it holds shape. Check for granule particles between your fingers. There should be no sugar grains remaining.
Add the vanilla, beat for 20 seconds to incorporate. Using a rubber spatula, fold in the vinegar and cornstarch. Gently.
Spread the pavlova mixture into an 8 inch circle. Make a bird's nest to hold your toppings.
Place pavlova in the oven. As soon as you close the oven door, reduce heat to 200°F . The pavlova will stay in the oven as it cools down to 200°F (93°C). Bake until the pavlova is firm and dry, about 90 minutes total. Do not open the oven while cooking or it will collapse.
Turn the oven off and let the pavlova cool inside the oven. It is best overnight. Once the pavlova is cool, you can store it covered at room temperature for up to 2 days.
Top the pavlova with whipped cream and fruits of your choice. you can make a double layer by doubling the mixture. it stacks well! Slice and serve.