Pre- heat oven 177C. Line two trays with baking paper. Have a large pastry bag ready with a 1/2 inch round tip.
In your electric mixer, fitted with the paddle attachment, beat the egg yolks and 2 tablespoons of sugar on high speed for 5 minutes or until the batter becomes thick and pale yellow. ( when you raise the beaters the mix should fall back into the bowl in a slow ribbon). 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 until soft peaks form and the whites are glossy. Graduallly add the 3 tablespoons of sugar and whip until stiff peaks form. Fold the whites into the egg yolk and flour mixture in three additions, mixing only until incorporated.
Transfer batter to the pastry bag and pipe the batter into 3 inch lady fingers. Leave a inch gap between fingers.
When you have piped all the fingers on the trays, sift the powdered sugar over the fingers. Bake for 8-10 minutes or until the lady fingers are firm but barely browned and are still spongy when pressed with a finger.
Leave fingers on the baking paper and place on a wire rack to cool for a few minutes..Remove from the baking paper with a flat spatula while still warm. If left to cook till cold they may stick to the paper and break. Allow the fingers to completely cool for use or storage. They can be frozen in the freezer in a plastic bag layered with parchment paper. Freeze for up to 2 weeks. They make about 4 1/2 dozen.