Preheat the oven to 200 degrees F. Line 2 baking sheets with parchment paper. Using a small glass and a pencil, draw 4 (3 1/2-inch) circles on each piece of paper. Turn the paper face down on the baking sheets.
In the bowl of an electric mixer fitted with the whisk attachment, beat the egg whites, cream of tartar, and salt on high speed until frothy. Add 2/3 cup of the sugar and continue beating on high speed until the egg whites form very stiff peaks. Whisk in the vanilla. Carefully fold the remaining 1/3 cup sugar into the meringue. With a large star - shaped pastry tip, pipe a disk of meringue inside each circle. Pipe another layer around the edge to form the sides of the shells.
Bake for 2 hours, or until the meringues are dry and crisp but not browned. Turn off the heat and allow the meringues to sit in the oven for 4 hours or overnight.
For serving, place each meringue on a separate plate and top the shell with berries.
Preheat the oven to 450 degrees F.
Place the strawberries, raspberries, blueberries and blackberries on a sheet pan and toss with the sugar and vanilla bean seeds. Roast in the oven for 20 minutes. Cool to room temperature before serving.