Beat egg whites and cream of tartar in a large mixing bowl until they form a dense white foam with stiff peaks. Sift sugar and cornstarch on top of egg whites. Pour vinegar and vanilla down side of bowl. Use the slowest speed to incorporate ingredients together. Do not over beat or over mix.

Spread the mixture on a parchment paper-lined baking tray into about an 8-inch circle. Place Pavlova in a preheated 425 degree oven on the middle shelf and immediately turn temperature down to 250 degrees. Cook for 1-1/2 hours. Turn the oven off and leave the Pavlova to cool thoroughly in oven before removing. Once cold, cover thickly with whipped cream and serve with sliced kiwi.