Place the chocolate, broken into pieces, in a mini-chopper. Chop the chocolate, then remove and keep to one side.
Now blend the coffee, 2 tablespoons boiling water and the sugar in a bowl.
Reserve 4 teaspoons of the crème fraîche, then add the ricotta cheese and the rest of the crème fraîche to the coffee mixture in the bowl and mix until smooth.
Lastly, stir in all but 1 tablespoon of the chopped chocolate and divide among 4 small glasses or cups.
Top with the reserved crème fraîche, sprinkle with the rest of the chopped chocolate, cover loosely with clingfilm and chill in the fridge until ready to serve.