Line an 8in/20 cm cake tin with a removable bottom with parchment or wax paper.
Beat together egg whites and salt until stiff peaks form.
Add sugar, 1 tbsp at a time, beating well until the meringue is very thick and glossy.
Sprinkle vinegar, cornstarch and vanilla over the meringue, then blend it gently but thoroughly.
Spoon meringue into the tin making a slight depression in the center. Place in 325 farenheit/160 centigrade oven for 30 minutes, then turn off the heat, leaving the meringue in the oven untill the oven is at room temperature.
Remove from oven and carefully peel off the paper. Whip cream until thick but slightly soft peaks form. Spread on meringue, then cover with fruit. (alternatively, you can fold some fruit into the whipped cream before spreading it over the meringue) Serve immediately. Do not put the cream onto the pavlova untill immediately before you will serve it.