Photograph: Brett Stevens
Preheat the oven to 140°C, fan 120°C, gas 1. Whisk the egg whites in a large, clean bowl until they form stiff peaks.
Gradually add the caster sugar to the egg whites, whisking all the time, until you have a stiff, glossy mixture. Whisk in the cornflour and vinegar.
Transfer a third of this meringue mixture to another bowl and sieve in the cocoa powder, stirring gently to combine.
Pile both the meringue mixtures on to a baking sheet lined with baking paper and swirl them together using a skewer so you end up with a round meringue about 20cm in diameter.
Bake the pavlova for 1 hour, then turn off the oven and leave it in the oven overnight.
To finish, whip the cream with the icing sugar and spoon on top of the pavlova. Peel and slice the mango and twist the leaves of the physalis to reveal the fruit. Top the pavlova with the sliced mango, physalis, chocolate curls and toasted coconut.
Get ahead: make the pavlova the day before; store in a cool, dry place.
Kitchen secret: we topped our pavlova with mango, chocolate curls, toasted coconut and physalis. For perfect chocolate curls, try chocolatetradingco.com – or make your own with a flat-bladed vegetable peeler. Toast your own fresh coconut shavings at 160°C, fan 140°C, gas 3, for 8-10 minutes.