Set your oven to 250°F (120°C). Line a baking sheet with parchment paper, drawing a circle about 8 inches in diameter as a guide.

In a large mixing bowl, beat the egg whites on medium speed until soft peaks form.

Gradually add in the sugar, one tablespoon at a time, ensuring it dissolves completely before adding more.

Continue beating until you reach stiff peaks and the mixture is glossy.

Gently fold in the vinegar and cornstarch using a spatula to achieve the perfect texture.

Spoon the meringue mixture onto the prepared parchment circle, spreading it out gently to create a slight well in the center.

Place the pavlova in the preheated oven for approximately 1 hour.

Once done, turn off the oven and let the pavlova cool completely inside the oven with the door slightly ajar.

While the pavlova is cooling, beat the heavy whipping cream with the powdered sugar and vanilla extract until stiff peaks form.

Once the pavlova has cooled, break it into pieces and layer it in a trifle dish or clear glass bowl with alternating layers of whipped cream and mixed berries.

Garnish with fresh mint leaves if desired. Serve immediately or chill until ready to serve.