Preheat oven to 120°C fan forced. Line an oven tray with foil, brush with melted butter, and dust with cornflour, shaking off excess. Mark a 24cm-diameter circle on foil.

Use an electric mixer to whisk egg whites in a clean dry bowl until soft peaks form. Gradually add sugar, one tablespoon at a time, beating well after each addition until meringue is thick, glossy, and sugar is dissolved.

Add cornflour, vinegar, and vanilla to meringue, whisking until just combined. Spoon meringue onto the foil, using the marked circle as a guide. Smooth sides and top, and use a small spatula to form little peaks around the edge.

Bake for 1 1/2 hours or until dry to the touch. Turn off oven and leave the pavlova in the oven with the door ajar to cool completely.

Once cooled, transfer to a serving plate or store in an airtight container until ready to use.

Whisk the cream and icing sugar in a medium bowl until firm peaks form.

Spoon cream onto the top of the pavlova. Decorate with strawberries, raspberries, and blueberries, and drizzle with passionfruit pulp.