Preheat oven to 350 degrees F (177 degrees C) and line two baking sheets with parchment paper.  To make the piping of the cookies easier, use a pencil and ruler to divide the parchment paper into three - 3 inch (7.5 cm) rows, with about 1 inch (2.54 cm) between rows.   Have ready a large pastry bag fitted with a 1/2 inch (1.25 cm) round tip.

In your electric mixer, fitted with the paddle attachment, beat the egg yolks and 2 tablespoons (25 grams) white sugar on high speed for about 5 minutes or until the mixture becomes thick and pale yellow.  (When you raise the beaters the batter should fall back into the bowl in a slow ribbon.)  Beat in the vanilla extract.  Sift the cake flour over the batter but do not fold in.

In a clean bowl, with the whisk attachment, whip the egg whites until foamy.  Add the cream of tartar and continue to beat until soft peaks form.  Gradually add the 3 tablespoons (36 grams) white sugar and whip until stiff peaks form and the whites are glossy.  Fold the whites into the egg yolk and flour mixture in three additions, mixing only until incorporated. 

Transfer the batter to the pastry bag and, holding the bag at about a 45 degree angle to the baking sheet, pipe the batter into 3 inch (7.5 cm) long ladyfingers, using the lines drawn on the parchment paper as your guide.  Pipe the batter leaving about a 1 inch (2.54 cm) space between the cookies.  

When you have piped all the cookies, place the powdered sugar in a wire strainer, and lightly sift the sugar over the tops of the cookies.  Bake for 8 to 10 minutes or until the ladyfingers are firm but barely browned and are still spongy when pressed with a finger.

Remove the baking sheets from the oven and slide the parchment paper from the baking sheets onto a wire rack.  Let the ladyfingers cool for a few minutes and release them from the parchment paper, with a flat spatula, while they are still warm.  If you left them completely cool before removing them from the parchment they stick and hard to remove without breaking.  Finish cooling the ladyfingers on the wire rack before using or storing.  If you are not using the ladyfingers right away, freeze them.  Ladyfingers stale very quickly unless they are soaked in a liquid.  To store, place in a plastic bag between layers of wax or parchment paper and freeze up to 2 weeks.

Makes about 4 1/2 dozen 3 inch (7.5 cm) Ladyfingers.