Beat together egg whites, salt, and cream of tartar to soft peaks in a large bowl. Beat in sugar, about three tablespoon at a time, until stiff and glossy peaks form. Sift cocoa and cornstarch over egg whites, and gently fold in. gently fold in vinegar, Vanilla, and melted chocolate.
Line a baking sheet with parchment paper, and spread the meringue into an eight-inch circle. Bake in the center of the oven for 1 1/2 hours until the outside is crispy and the center is soft. using a metal spatula, loosen the meringue from the parchment paper, and remove to cool on a wire rack. Allow to cool completely, about one hour.
Whip cream with the sugar, and spread over the meringue. Arrange strawberries decoratively over the top, and drizzle with chocolate.