Lincoln Log Roll

Beat egg whites to soft mound; gradually add ½ cup sugar, beating until stiff peaks form. Beat egg yolks, ¼ cup sugar, baking powder, vanilla and salt until very thick. Fold into whites, then fold in flour. Grease bottom of 15 x 10 x 1 ½-inch jelly roll pan, line with waxed paper, then grease again. Spread batter in pan. Bake at 375 degrees for 12 to 15 minutes or until golden brown. Turn out into a towel sprinkled with confectioner's sugar. Peel off waxed paper. Roll cake and towel together; cool. Unroll and spread with preserves. Roll up, wrap in plastic wrap.