Preheat the Oven:Preheat your oven to 300°F (150°C). Line a baking sheet with parchment paper and draw a 9-inch circle on the paper as a guide.
Prepare the Meringue:In a clean mixing bowl, beat the egg whites on medium speed using an electric mixer until they form soft peaks. Gradually add the granulated sugar, one tablespoon at a time, while continuing to beat. The mixture should become glossy and form stiff peaks.
Add Vinegar, Cornstarch, and Vanilla:Gently fold in the white vinegar, cornstarch, and vanilla extract. This helps stabilize the meringue and gives it a chewy center.
Shape the Pavlova:Spoon the meringue onto the parchment paper, using the circle as a guide. Smooth the edges and top with a spatula, creating a slight well in the center for the toppings.
Bake:Place the meringue in the preheated oven and immediately reduce the temperature to 250°F (120°C). Bake for 1 hour, then turn off the oven and let the pavlova cool completely inside the oven with the door closed (about 2 hours).
Prepare the Topping:While the pavlova cools, whip the heavy cream with powdered sugar until soft peaks form.
Assemble:Once the pavlova is completely cool, top it with the whipped cream and arrange fresh fruits on top.
Serve:Slice and serve immediately. Enjoy the crispy exterior and soft, marshmallow-like interior!