Nigella Lawson’s chocolate raspberry pavlova

6 large free-range egg whites
300g caster sugar
3 tbsp cocoa powder, sieved
1 tsp balsamic or red wine vinegar
50g dark chocolate, finely chopped
For the topping
500ml double cream
500g raspberries
2-3 tbsp coarsely grated dark chocolate

01.Preheat the oven to 180°C/fan160°C/gas 4 and line a baking tray with baking paper. Beat the egg whites until satiny peaks form, then beat in the sugar, a large spoonful at a time, until the meringue is stiff and shiny. Add the cocoa, vinegar and chopped chocolate, then gently fold until the cocoa is thoroughly mixed in. Mound onto a lined baking sheet in a fat circle about 25cm in diameter, smoothing the sides and top. Place in the oven, then immediately reduce the temperature to 150°C/fan130°C/gas 2 and cook for 1-1¼ hours.

02.When the meringue is ready it should look crisp around the edges and sides, and be dry on top, but when you prod the centre you should feel the promise of squidginess. Turn off the oven and open the door slightly, then let the chocolate meringue disc cool completely.

03.When you’re ready to serve, lift onto a large, flat-bottomed plate. Whisk the cream until thick but still soft, pile it on top of the meringue, then scatter over the raspberries. Sprinkle the fruit haphazardly over the top, letting some fall, as they will, on the plate’s rim. Sprinkle over the grated chocolate to serve.