Step 1Position a rack in the center of the oven and preheat to 275 degrees. Firmly trace six (2 1/2-inch) circles on parchment paper, then invert paper onto a baking sheet.
Step 2Using an electric mixer fitted with a whisk attachment, beat the egg whites and pinch of salt in a large, clean bowl until soft peaks form. Gradually beat in 6 tablespoons sugar, and continue beating until medium-firm peaks form. Mix the remaining 2 tablespoons sugar and cornstarch in a small bowl, then gradually beat sugar-cornstarch mixture into meringue. Continue beating until very stiff peaks form. Beat in the vinegar and rose water.
Step 3Divide the meringue between circles, spooning it to fill each circle completely. Bake until the outside is dry to the touch and the meringues are just beginning to color slightly, about 35 minutes. Turn oven off and open door just slightly, and leave the meringues in the oven until completely cool. The meringues can be made up to 5 days in advance, and stored in an airtight container at room temperature.
Step 1In a large bowl, toss the berries with the syrup to coat completely.
Step 2Using an electric mixer, beat the cream until soft peaks form.
Step 3To serve, spoon a dollop of whipped cream on to the center of each of 6 plates. Top each with 1 meringue. Spoon the berries over meringue and top with remaining whipped cream, dividing evenly. Drizzle with additional syrup if desired and serve.