Preheat oven to 120°C fan forced. Line two trays with baking paper. Draw 4 x10cm rounds onto each tray, turn paper over so marked side down.
Pour the egg whites in the bowl of an electric mixer. Add cream tartar. Whisk on high speed to stiff peaks. Add the sugar, 1 tablespoon at a time. Once all the sugar has been added, scrape the sides of the bowl and whisk a further 5 minutes or until the mixture is stiff and glossy. Add the vinegar and whisk 1 minute.
Divide mixture between 8 rounds. Bake for 1 hour. Turn the oven off, leave door ajar and allow pavlovas to cool completely.
For the topping; whip the cream and 2 tablespoons icing sugar together to soft peaks. Swirl through the custard. Dollop over pavlovas. Top with raspberries and pistachio. Dust with remaining icing sugar. Serve.