Heat oven to 350 F.  Line a baking sheet with parchment.  With an electric mixer, beat egg whites and salt in large bowl on medium speed until firm peaks form.  On low speed, add the sugar 1 tablespoon at a time until the meringue forms stiff peaks.  Whisk in the cornstarch and vanilla.

Divide the meringue into six 4-inch circles on the baking sheet.  With a large spoon, make indentations in the middle of each.  Place the baking sheet in the oven and lower the temperature to 300F. Bake 30 minutes, then turn off the oven and leave the baking sheet in for another 30 minutes.  To serve, whip the cream to soft peaks and stir in the lemon curd. Dollop onto the meringues and top with the grapes.  Garnish with almonds, if desired.