Line a loaf tin generously with cling film allowing a lot of cling to drape over the sides that will be able to seal it when filled.
Add cream to a large bowl large enough to take all the other ingredients. Softly whip then fold in crème de cacao. Then fold in all other ingredients.
Transfer to your cling lined tin and freeze for at least 4 hours
When almost ready to serve prepare chocolate sauce by melting the chocolate and butter in the cream over a low heat stirring constantly until melted. Tip into serving vessel and allow to cool slightly.
Remove cake from freezer, peel off cling and transfer to platter. Drizzle a little sauce over the platter and bring some to the table so you can add more as needed. If not using all in one go just slice what is needed and drizzle with chocolate sauce and put remaining back in freezer it melts very quick.