Grease and flour a parchment-lined baking sheet, or a springform pan. Preheat the oven to 275 degrees. Beat the egg whites with the salt and cream of tarter in the large bowl of a standing mixer until soft peaks form. Gradually add the sugar, and continue beating till it will hold stiff peaks. Beat in the cornstarch, vinegar and vanilla.

Using a rubber spatula, mound the meringue in a circle on the prepared baking sheet, or into the springform pan. Either way, make the sides slightly higher than the center, to create a bit of a well for the whipped cream. Bake in center of oven for 1 hr 15 minutes, then allow to cool inside the oven with the door slightly ajar. The outside will be dry, and will be a pale, cream colour. The surface may crack, but the inside will be moist and marshmallowy.

Just before serving, whip the cream (adding 1 tsp vanilla and 2 tbsp sugar, if desired). Pile the cream onto the meringue and top with the fresh, sliced fruit. Serve immediately.