Mix together flour, Clabber Girl Baking Powder and salt. In a small bowl beat together eggs and sugar until well mixed and lemon-colored. Add vanilla. Stir in flour and mix until well combined.
Spread batter into a 15x10-inch jelly roll pan that has been greased and lined with parchment paper (waxed paper would work well also).
Bake in a preheated 400 degree F. oven for about 12 to 15 minutes. When cake is done, immediately turn out onto cloth that has been sprinkled with confectioners' sugar. Remove paper from cake, cut off crisp edges and roll up cake. Cool on wire rack.
When cake is cooled, unroll and spread cake with jam or preserves. Re-roll and sprinkle with additional powdered sugar.