Preheat the oven to 120C. Line a baking sheet with greaseproof paper and mark out a 24cm diameter circle. Spray with some oil, then dust with cornflour and shake off the excess.
Place egg whites in a very clean bowl and beat until soft peaks form. Add the sugar, a tablespoon at a time and continue to beat on high until all the sugar has been added and is thoroughly dissolved. Add sifted cornflour and vinegar, fold until combined.
Place pav mix in the centre of the circle on the baking sheet, and use a spatula or palate knife to very gently spread out the mix to the edges. Make sure to scrape up the sides to create an outside “wall” and that a slight hollow is left in the centre. Bake for 1.5 hours, then turn off oven and leave the door ajar. Allow pav to cool for about 5 hours, then transfer to an airtight container.Using electric beaters, whip cream until thick and velvety. Stir in wattleseed extract. Spoon over the pav and decorate with berries and chocolate shavings.