Melt the butter with the chocolate. Stir in the chestnut cream (the chocolate should no longer be hot).
Separate the eggs. Mix the egg yolks and mix with the chocolate mixture. Beat the egg white until stiff and fold in.
Pour into a greased flat baking pan. Bake at 160 ° C (top / bottom heat) for approx. 50 minutes. Let it cool down and fall. Serve with vanilla sauce and a whipped cream.