Put the egg yolks into bowl together with the sugar and mix until the mixture has light consistency.

In a separate large bowl, stir the mascarpone with a wooden spoon to soften it, then gradually beat in the egg yolk mixture. Between each addition, beat well until the mixture is smooth before adding more.

Then in a separate bowl whisk the egg whites until they form soft peaks. Lightly fold this into the mascarpone mixture and then put the bowl to one side.

Break the biscuits in half, then pour the coffee and rum into a shallow dish and dip the sponge fingers briefly into it, turning them over – they will absorb the liquid very quickly.

Now simply layer the desserts by putting 3 of the soaked sponge halves into each glass, followed by a tablespoon of mascarpone mixture and a layer of chopped chocolate. Repeat the whole process, putting 5 halves in next, followed by the mascarpone, finishing with a layer of chopped chocolate and a final dusting of cocoa powder.

Cover the glasses with clingfilm then chill in the refrigerator for several hours and serve straight from the fridge.