Beat the egg whites until stiff.Add the sugar and continue beating until it's like a meringue. Quickly beat the egg yolks in a separate container and fold in along with the vanilla. Fold in the flour.
Fill a pastry bag with the mixture and pipe onto a buttered and floured pan. They should be approximately 3“ long.
Sprinkle the ladyfingers with powdered sugar and bake at 375 for 12 minutes.