1. Preheat the oven to 250°F and line a baking sheet with parchment paper. Draw an 8-inch circle as a guide if desired.

2. In a clean mixing bowl, beat the egg whites until soft peaks form.

3. Add the granulated sugar gradually, beating continuously until the meringue is thick, glossy, and holds stiff peaks.

4. Gently fold in the cornstarch, white vinegar, and vanilla extract.

5. Spoon the meringue onto the parchment and shape it into a round, creating a shallow well in the center.

6. Bake for 1 hour and 15 minutes, then turn off the oven and let the pavlova cool inside with the door slightly open for 1 hour.

7. Beat the heavy whipping cream with the powdered sugar until soft to medium peaks form.

8. Transfer the cooled pavlova to a serving plate and fill the center with whipped cream.

9. Top with strawberries, raspberries, blueberries, pomegranate seeds, and mint leaves.

10. Slice gently and serve right away.