Preheat oven to 350°.
Lightly spoon flour into a dry measuring cup; level with a knife. Combine flour, baking powder, baking soda, and salt, stirring with a whisk.
Place 1/3 cup granulated sugar and butter in a medium bowl; beat with a mixer at medium speed until well blended. Add egg substitute; beat just until combined. Add flour mixture and buttermilk alternately to sugar mixture, beginning and ending with flour mixture; beat well after each addition. Stir in vanilla (batter will be thick).
Spoon batter into an 8-inch round cake pan coated with cooking spray. Bake at 350° for 22 minutes or until a wooden pick inserted in center comes out clean. Cool in pan on a wire rack for 10 minutes. Remove from pan; cool completely on wire rack. Sift powdered sugar over top of cake.
Combine berries and 1 tablespoon granulated sugar; toss to coat. Let stand 15 minutes. Serve berry mixture with cake.