Preheat the oven to 350 degrees F.
Combine egg whites, salt, and white vinegar together in the bowl of an electric mixer and beat on high speed until soft peaks form. Combine the 3/4 cup sugar and cornstarch together in a small bowl and add to the egg whites in thirds, whisking each addition in completely. Add the vanilla and beat until stiff peaks form. Line a baking sheet with parchment paper and spoon the meringue in 8 big spoonfuls, using a spoon to spread them in a circle, and then make an indent in each. Bake for 10 minutes, lower the heat to 200 degrees F, and bake for another hour. Turn off the heat and cool the meringues in the oven for an hour, propping the door open with a wooden spoon. Meanwhile, whip the cream together with the remaining 2 tablespoons of sugar. In a small bowl, crush 1/2 cup of the blueberries with a potato masher or a spoon to release their juice. Fold those and the rest of the blueberries into the cream if you like, or use as a topping over the egg whites and cream. Evenly distribute the cream on the meringues, filling in the indentations. Top with juicy blueberries and serve.
Recipe courtesy of My Father's Daughter by Gwyneth Paltrow.