Preheat the oven to 300°F. Line a sheet pan with parchment paper, draw a 9-inch circle in the center, and flip the paper so the drawn side is underneath.

Use a clean, grease-free mixing bowl and whisk attachment. Start whipping the egg whites alone on medium speed until they become frothy and opaque.

Add the 1/8 teaspoon salt and continue whipping. As soft peaks form, pour the sugar in a slow, thin stream while the mixer runs.

After the sugar is incorporated, increase to high speed and beat until firm, glossy peaks form, about two more minutes.

Stop the mixer. Use a rubber spatula to gently fold in vanilla extract, vinegar, and cornstarch until mixed.

Spoon the meringue onto the center of the traced circle, spreading it to the edges and building up the rim slightly.

Place the pan in the oven, reduce the heat to 250°F, and bake for 1½ hours.

Turn off the oven and leave the meringue inside until it turns crisp and pale, about 1 hour.

Remove the pavlova from the oven and let it cool fully on the pan.

Once cool, top with whipped cream and fruit as desired.