Grease a deep 8½ inch/22cm round cake pan. Line the base and sides with non stick baking paper.
Melt the chocolate in microwave or in a bain marie.
Beat the eggs and sugar until thick and creamy.
Beat in melted chocolate until combined.
Then using a spatula, gently fold in cream and Frangelico.
Pour mixture into pan. Place pan in baking dish and pour enough boiling water into the baking dish to come halfway up side of pan.
Bake 30 minutes, cover with foil and bake 30 minutes more.
Discard the foil, remove the cake pan from the baking dish, cool cake in pan.
Turn cake onto serving plate cover and refrigerate overnight.
Ganache Topping (optional)
Heat ½ cup cream until hot but not boiling. Pour over semi sweet (dark) chocolate and allow to stand for 3-5 minutes. Then stir gently until smooth. Spread over the cold cake.
Heat 1½ cream until hot but not boiling. Pour over white chocolate and allow to stand for 3-5 minutes. Then stir gently until smooth. Pipe in circles around the top of the cake. Draw a toothpick gently from the inside circle to the outside and even intervals around the cake.