Preheat oven to 325ºF. Sift flour with 3/4 cup sugar.
In large bowl, beat egg whites and salt with electric mixer until foamy; add cream of tartar and beat until soft peaks form. Gradually beat in 1 cup sugar, sprinkling 1/4 at a time and beating well after each addition, until stiff peaks form. With a large silicone spatula, gently fold in vanilla. Gently fold in flour mixture 1/4 at a time over egg whites with an over and under motion after each addition. Fold additional 10 strokes after last addition until flour is well blended. Gently transfer batter to ungreased pan. With spatula or knife, cut through batter gently.
Bake on lower oven rack 55-60 minutes or until top is browned and cake tester comes out clean. Invert pan on counter to cool cake thoroughly (about 2 hours) before removing from pan. Run knife around the sides and center of cake to loosen.
In large bowl, whip cream, confectioners’ sugar, and vanilla on high speed until stiff peaks form. Cut cooled cake horizontally and fill with whipped cream. Spread a thick layer of whipped cream on top of cake and garnish with fresh berries just before serving.