Bring butter and water to boil, add in cake flour mix till no lumps. Allow to cool. Put mixture into mixer. Beat in 1 egg at a time. Pipe mixture onto trays. Bake at 180° for 10 minutes, then at 160° for 10 minutes, then at 140° for 10 minutes, then bake at 100° for 1 hour. Leave in oven for a couple of hours. Cut in the middle and take out excess dough. Fill with whipped cream. Close. Put melted chocolate over.