Preheat oven to 250°F. Add salt to egg whites, and beat until stiff. Gradually add the sugar, beating continuously, until all the sugar is well beaten in, and the mixture is stiff. Fold in the corn flour, vanilla, and lemon juice.
Scoop mixture on to an aluminum covered oven tray, in a round dish shape. Make a slight depression in the center, and bring sides up a little. Bake for 1 1/2 hours.
When you are ready to serve your Pavlova, pile Cool Whip into the depression, and top with fruit. Enjoy!