Berry Pavlova Roulade

Name: Berry Pavlova Roulade
Ingredients: 5 egg whites, at room temperature; 1 pinch kosher salt; 1/8 teaspoon cream of tartar (optional, but adds some strength if using older eggs); 3 tablespoons cold water; 1 1/4 cups superfine sugar; 1 tablespoon plus 1 teaspoon cornstarch; 1 teaspoon vanilla extract; 1 teaspoon vinegar (white wine, cider, or distilled); 4 cups fresh berries for filling and topping, such as raspberries, blueberries, or sliced strawberries; Confectioners’ sugar for dusting; 2 cups cold heavy whipping cream; 1 to 2 tablespoons confectioners’ sugar