Line an 11"x16" jelly roll tray (swiss roll tin) with the baking paper, and preheat the oven to 325ºF (160ºC).
Mix the cornstarch, vanilla and vinegar together in a small bowl, until smooth; set aside.
Whisk the egg whites in a clean, dry bowl until stiff, then whisk in a little sugar, and a little of the cornstarch paste, and continue adding until they are completely mixed in.
Spoon the egg white mixture into the prepared tray. Smooth out the surface with a spoon or a spatula.
Bake for approximately 25 minutes, until golden colored.
Place a towel on the counter, topped with a sheet of baking paper, sprinkled with confectioner's sugar and turn out the meringue onto the paper.
Peel away the lining paper and place a new piece of baking paper on top, then roll the meringue, starting from the short side, using the towel as an aide. Let cool.
Whip the heavy whipping cream until stiff peaks form.
When the meringue roulade is cool, unroll it, and remove the top paper; spread the whipped cream over the entire layer.
Sprinkle with the berries and re-roll the dessert, placing the seam side down. Dust generously with confectioner's sugar.
Carefully move the meringue roulade to a serving plate, and add a few berries for decoration.