Preheat the oven to 200°F.
Line a baking sheet with parchment paper. Use the bottom of a cake pan to trace a circle on the parchment paper. This will help you shape your meringue.
In a stand mixer, use a whisk attachment to beat the egg whites on low until they start to foam. Increase the speed to medium until the egg whites become opaque and form soft peaks. Very slowly, add your sugar a tiny bit at a time. Continue beating until stiff peaks form. Using a rubber spatula, fold in cornstarch, vinegar, salt, and vanilla. Continue folding until the meringue is shiny and moldable.
Pour mixture out onto the parchment paper, trying to keep it inside your traced circle. Shape the meringue with the round side of a large spoon. Alternately, use a pastry bag fitted with a large plain tip and pipe meringue in dollops within the circle.
Bake for about 1 hour and 30 minutes then turn off your oven and leave the door ajar, leaving the meringue to cool completely in the oven.
Top with fresh fruit, nuts, whipped cream, curd, jam, or a combination.