Preheat the oven to 180C/Gas4. Line a baking tray with greaseproof paper. Draw a 20cm/8inch circle on the paper.
Whisk the egg whites with half the sugar and the salt in a clean bowl until soft peaks form. Continue beating while adding the remaining sugar until stiff and shiny. Sprinkle over the cornflour, cream of tartar, vinegar and vanilla essence and fold in gently with a metal spoon.
Mould the egg white mix onto the paper within the circle. Peak the sides and leave a slight depression in the middle. Place in the oven and immediately reduce the heat to 150C/Gas 2 and cook for 1 1/4 hours.
Turn off the oven, leave the door slightly ajar and allow to cool completely. Remove the pavlova from the baking paper, fill the centre with the whipped cream and then top with the fruit.