Grease a 15 ½" x 10 ½" jelly-roll pan and line with parchment paper.
Beat egg whites in a large bowl until soft peaks form. Gradually beat in ¼ cup sugar and continue beating until stiff peaks form. In a separate bowl, beat egg yolks, vanilla and remaining 1/4 cup sugar. Continue beating until thick, about 6 minutes. Mix in flour just until blended. Gently fold egg yolk mixture into beaten egg whites. Spread the batter in the prepared pan. Bake for about 12 minutes or until cake top springs back when lightly touched.
To remove cake from pan and cool, sift confectioner's sugar over a clean kitchen towel. Loosen the edges of the cake from the sides of the pan with a small knife. Inver cake onto the prepared towel and carefully peel off the parchment paper. Starting from one short edge, roll up the cke and the towel together, like a jelly roll. Cool completely on a wire rack. After cooling, unroll cake and spread with pastry cream, jams, lemon curd or whichever filling suits your fancy. Roll up from the short side, without the towel this time and transfer, seam side down, to a serving platter. Sprinkle with confectioner's sugar or frost.