Mix pudding, gelatin, sugar and water and egg yolks. Bring to boil. Remove from heat. Add 1/4 cup lemon juice. Cool (not set). Fold in Cool Whip (1 cup).
Cut cake into 1 1/4 inch squares, add to above mixture. Pour into 10 inch springform or large mixing bowl or angel cake pan. Next day frost with Cool Whip or 1 cup whipped cream.