Preheat oven to 200 degrees C. Grease a 20cm springform pan and dust lightly with half the cornflour.
Beat egg whites, in a glass or ceramic bowl, until stiff and glossy. Combine cream of tartar, sugar and cornstarch; gradually beat in to the egg whites. Sprinkle vinegar over egg white mixture, then fold it in very gently.
Pile meringue into prepared pan. Spread to the sides leaving a slight depression in the center. Place in oven and immediately turn oven down to 120 degrees C. Bake for 1-1 1/2 hours. Turn oven off and open the door, but leave pavlova in the oven for 15 minutes. Remove pavlova to a draft free spot. Very carefully remove rim of springform pan, and allow pavlova to cool completely. There may be a slight sinking in the centre. Carefully remove pavlova from pan base and place on serving platter.
Whip cream, vanilla extract, and icing sugar until firm peaks form. Gently spread over the meringue.
Remove the pulp from the passionfruit and spoon over cream. Chill until serving.