Line the bottom and sides of an ungreased 9" round springform pan with split ladyfingers, trimming off the bottoms to make ladyfingers stand. Set aside. In a double boiler over medium heat, cook and stir chocolate, sugar and water until chocolate is melted and smooth. In a separate bowl, beat egg yolks and gradually add to chocolate mixture, stirring constantly until smooth; cool. Blend together butter, powdered sugar and vanilla; mix well.
Add chocolate mixture; stir well and set aside. With an electric mixer on high speed, beat egg whites until stiff peaks form; fold into chocolate mixture. Spoon mixture into lined pan. Arrange any remaining ladyfingers on top. Top with whipped cream and sprinkles. Refrigerate until ready to serve. To serve, remove outer ring of springform pan.
Place cake on cake stand. Use a tiny dot of whipped cream to add a sliced almond to each of the ladyfingers to resemble fingernails.
