Pavlova is named after Russian ballerina Anna Pavlova. She toured Australia and New Zealand in the 1920s, and both countries take credit for inventing the dessert. Some people say it was inspired by her tutu; others say it was created in the spirit of her light, airy style of dancing.
Preheat the oven to 275˚ and line a baking sheet with parchment paper. Using a plate or cake pan as a guide, trace a 9-inch circle on the parchment with a pencil, then flip over the parchment on the baking sheet (the circle should still be visible); set aside.
Make the meringue: Whisk the egg whites, 1/4 teaspoon vinegar and the salt in a large bowl with a mixer on medium speed until soft peaks form, 2 to 4 minutes. Gradually beat in the sugar, 1 tablespoon at a time, until dissolved. Increase the mixer speed to medium high and beat until stiff peaks form, 3 to 4 minutes. Add the cornstarch, vanilla and the remaining 1/2 teaspoon vinegar and beat until just combined, 10 to 15 seconds.
Spread the meringue into a 9-inch round on the prepared baking sheet (use the pencil marking as a guide) and make a shallow well in the center. Transfer to the oven and immediately reduce the oven temperature to 225˚. Bake until crisp and dry, about 2 1/2 hours. (The meringue should still be white or a very pale cream color.) Turn off the oven and open the door slightly (use the handle of a wooden spoon to prop it open about 1/2 inch). Let the meringue cool completely in the oven, about 1 1/2 hours. Carefully remove the meringue from the parchment and transfer to a platter.
Make the whipped cream: Beat the heavy cream, sugar and vanilla in a large bowl with a mixer on medium-high speed until soft peaks form, about 2 minutes.
Just before serving, top the meringue: Gently stir the passion fruit pulp to loosen. Top the meringue with the whipped cream and passion fruit. Serve immediately.