Prep your setup. Preheat your oven to 250°F (130°C). Line a baking sheet with parchment paper. Draw six 3-inch circles on the parchment as guides for your pavlovas, then flip the paper over (so you don't get pen on your meringues – rookie mistake I've definitely made before).
Make that meringue shine. In a completely clean and dry bowl (seriously, even a drop of yolk or water will ruin this), beat the egg whites on medium speed until soft peaks form. Think of it like a little white mountain range starting to appear.
Now, the crucial part: gradually add sugar, about a tablespoon at a time, while continuing to beat. After each addition, beat for about 10 seconds before adding more. This patience is what separates good pavlovas from great ones. Keep beating until the mixture is glossy and holds stiff peaks. When you rub a little between your fingers, it should feel smooth (not gritty).
The secret stabilizers. Sprinkle the cornstarch over your glossy peaks, then add the vanilla and vinegar. Fold everything together gently with a rubber spatula. Think of it as tucking the meringue into bed – gentle and with care.
Shape your clouds. Spoon or pipe the mixture onto your prepared baking sheet, following those circles you drew. Use the back of a spoon to create a small well in the center of each meringue (this is where your berries will sit later – think ahead!).
The low and slow bake. Bake for 1 hour to 1 hour and 15 minutes. The outside should be crisp and very pale (not brown!), while the inside remains marshmallowy. Turn off the oven and leave the pavlovas inside with the door slightly ajar until completely cool. This prevents the dreaded crack-attack from sudden temperature changes.
Whip it good. When you're ready to serve, whip the heavy cream with powdered sugar and vanilla until soft peaks form. Don't overwhip unless you're trying to make butter (which, different recipe altogether).
Make it pretty. Top each cooled pavlova with a dollop of whipped cream, a generous pile of fresh berries, a drizzle of honey, and a tiny sprinkle of lemon zest if you're feeling fancy. Add a mint leaf for that "I'm a professional" touch.