Preheat oven to 250 degrees. Line a baking tray with baking paper and draw a 8 inch circle on the paper. Beat the egg whites with salt until peaks form (approximately three minutes). Beat in the sugar, 1/3 at a time, until the meringue is stiff. Add the corn flour, vinegar, and vanilla and beat at a very low speed. Mold onto the paper -- line baking tray within the circle, making a crater in the middle of the meringue. Cook in oven for 1 ½ hours. When Pavlova has cooled completely, top with whipped cream and sliced fruit of your choice. (We suggest strawberries, passionfruit, or banana)