Preheat the Oven: Preheat your oven to 250°F (120°C). Line a baking sheet with parchment paper and draw a 9-inch circle on the paper to guide the meringue shape.

1. Whip the Egg Whites: Beat the egg whites in a clean mixing bowl on medium speed until soft peaks form. Gradually add sugar, beating until stiff peaks form and the mixture is glossy.
2. Add Vanilla, Vinegar, and Cornstarch: Gently fold in vanilla extract, vinegar, and cornstarch to stabilize the meringue.
3. Shape the Meringue: Spoon the meringue mixture onto the parchment circle, smoothing the top and sides, and creating a well in the center.
4. Bake the Meringue: Bake the meringue for 1 1/2 hours or until crisp and dry. Turn off the oven and let it cool in the oven with the door slightly ajar.
5. Whip the Cream: Beat the heavy cream, powdered sugar, and vanilla extract until stiff peaks form.
6. Prepare the Berries: Hull and slice strawberries, and combine them with raspberries and blueberries. Optionally drizzle with honey or maple syrup for sweetness.
7. Assemble the Pavlova: Once the meringue has cooled, place it on a platter. Spoon whipped cream into the center, spreading it evenly, and top with berries.
8. Garnish and Serve: Garnish with fresh mint leaves and extra berries. Serve immediately or chill for 1-2 hours.