Preheat oven to 375 degrees. Thoroughly grease a jelly roll pan approximately 10" by 15". Cut a piece of parchment or waxed paper about 1 inch larger on all sides than the baking pan. Press paper into the baking pan allowing the excess to hang over the edges.
Mix potato starch, cake meal, baking powder, and salt in a medium bowl with a fork or whisk.
In the small bowl of an electric mixer, beat the egg yolks until light and fluffy. Gradually add the sugar and beat until creamy. Add the vanilla and blend well.
In the large bowl of an electric mixer, beat egg whites until stiff but not dry. Gently fold in the yolk mixture. Next sift the dry ingredients into the batter while continuing to run the mixer on fold.
Pour batter into prepared pan and spread with a spatula to distribute it evenly. Bake in the center of the oven for 12 minutes. [Do not over cook or burn.] Cake should spring back when touched.
Remove from oven and immediately loosen the edges of the cake with a small spatula. Turn cake out onto aluminum foil or clean dish towel that has been generously sprinkled with confectioners' sugar. Remove parchment paper.
Sprinkle with confectioners' sugar over cake. Spread preserves evenly over the cake. Roll up gently from the long edge. Dust with confectioners' sugar. Let cool completely.
To serve, cut ino slices approximately 1 inch thick, and display neatly on serving platter. Top with whipped cream if desired. The roll can also be filled with whipped cream, ice cream, or a custard filling.