1.Preheat oven to 120°C/250°F. Line oven tray with foil; grease foil, dust with cornflour, shake away excess. Mark 18cm (7-inch)circle on foil.
2.Beat egg whites in small bowl with electric mixer until soft peaks form; gradually add sugar, beating until sugar dissolves. Add extract and vinegar; beat until combined.
3.Spread meringue into circle on foil, building up at the side to 8cm (3 inches) in height. Smooth side and top of pavlova gently. Using spatula blade, mark decorative grooves around side of pavlova; smooth top again.
4.Bake pavlova about 1½ hours. Turn oven off; cool pavlova in oven with door ajar.
5.Cut around top edge of pavlova (the crisp meringue top will fall on top of the marshmallow centre). Serve pavlova topped with whipped cream, berries and passionfruit.
It is fine to use just one 300ml carton of cream for this recipe.Note