Using a clean and perfectly dry bowl, beat egg whites. When soft peaks form, add sugar gradually.
Beat until very stiff, continue beating and add salt, then vinegar, and finally vanilla a few drops at a time.
Beat in the cornstarch and keep beating until the mixture is really glossy and will stand when cut with a knife.
Cover a baking pan with a sheet of parchment paper, tip the pavlova mix into the center of the pan and spread it into around about 8 - 9 inches across, leave the center slightly caved inches
Place on rack in center of oven and cook for one hour, then turn oven off and leave until oven is cold.
Do not open the oven at all until it is cold. If you are unsure, it's better to leave in too long than open early.
This pavlova has a slightly crisp outside and is like marshmallow on the inside. You may dress it several ways, spread with a layer of thick whipped cream that has had 1/4 teaspoon of vanilla and 1 teaspoon of sugar added or pastry cream. This is covered with sliced fruit, whatever is in season - strawberries, raspberries, sliced (peeled) kiwifruit the choice is yours.