Line a large baking tray with baking parchment. Preheat the oven to 110 degrees/gas mark 1/4.
Put the eggs whites in a large, very clean bowl and whisk with an electric beater until opaque, verging on stiff, but still with a little wobble. Continue to whisk while adding the sugar ; the volume will continue to increase and the whites will turn glossy.
Spoon the stiff, glossy mixture onto the baking tray and use a spatula to spread the mixture into a rough circle of even thickness, about 5 cm.
Cook for 2 hours, then tun the oven off and leave the pavlova to cool in the oven with the door ajar.
Meanwhile, place the chopped rhubarb and sugar into a small pan and cook over a low heat for 20minutes or until tender.
Transfer the rhubarb to a bowl with a slotted spoon, thus leaving the juice in the pan.
Add the raspberries and sweet wine, or water to the pan and cook over a low heat for 5-10 minutes. Return the rhubarb to the pan, mix and leave to cool.
Whip the double cream until it has thickened slightly, but not clumpy and dry.
Smother over the cooled pavlova and top with the cooled, pink hued rhubarb and raspberry and their juices.