This is absolutely nothing like an English trifle, but very delicious nevertheless—I often wonder which came first, the English or the Neapolitan version! What is amusing is that the name, translated literally, means English soup—which has never struck me as being terribly complimentary!
Mix the rum and liqueur in a bowl and pour half into a second bowl. Strain the ricotta into one of the two bowls and mix the alcohol and the ricotta together thoroughly.
Grate the chocolate and mix about one third of it into the ricotta mixture.
Place the granulated sugar and the vanilla extract in a small pan with the water and melt together until you have a smooth caramel syrup. Allow to cool to hand heat, then pour this into the ricotta mixture gradually, stirring constantly.
Dip the sponge cake in the remaining rum and liqueur mixture and arrange a layer in the base of a pretty bowl. Pour over the ricotta mixture, then cover with another layer of dipped cake.
Continue until all the cake and the ricotta mixture have been used up, finishing with a layer of ricotta. Cover with the remaining grated chocolate and leave to chill in the refrigerator for 1 hour before serving.
You can also make this in individual ramekins or cups. If you wish, you could use mascarpone cheese instead, but the texture is quite different.