Heat the oven to  150ºC (300ºF).

Using a standing-mixer, beat the egg whites until they turn white and start to get fluffy.

Keep beating and add the sugar a little bit at a time.

Add the vanilla extract, vinegar, cornflour and water while still beating.

Continue to beat the mixture until it is thick and glossy (see the photo in the post for the ideal thickness).

Trace a circle on a piece of baking-paper, using a dinner plate as a guide.  Turn the paper upside-down (so you don't get lead in your pavlova!) and place it on a cookie tray.

Scrape out the mixture and shape it into a circular, flat mound.  If it sticks to your utensils, dip them in water and then cotinue.  Smooth the egg whites until you have the shape you want.

Bake it in the oven for 40 - 45 minutes, then turn the oven off, and let the pavlova cool in the oven.

When it is cool in can be kept for two or three days in a dry place.  Just before serving, whip the cream until thick, and decorate it with your choice of fruit.