Grease and flour a 15x10x1-inch baking pan; set aside. In a medium bowl beat egg yolks with an electric mixer on high speed about 4 minutes or until thick and lemon-colored. Wash beaters thoroughly. In a large bowl combine egg whites, vanilla, and salt. Beat on high speed until soft peaks form (tips curl); gradually add the 1/2 cup sugar, beating until stiff peaks form (tips stand straight). Fold yolks into whites; carefully fold in flour and nuts. Spread in prepared pan. Bake in a 375 degree F oven for 12 minutes or until top springs back when lightly touched.
Immediately loosen edges of cake from pan and turn out onto towel sprinkled with powdered sugar. Starting at short side, roll up cake and towel together. Cool on a wire rack.
Meanwhile, beat whipping cream and the 2 tablespoons sugar with an electric mixer on medium speed until stiff peaks form. Unroll cake; remove towel. Spread the sweetened whipped cream over cake to within 1 inch of edges. Roll up. Cover and chill up to 2 hours. Makes 10 servings.