Step 1

Combine the coffee, rum and Marsala in a shallow bowl. One at a time, dip roughly half the sponge fingers into the mix for just long enough to become heavy but not fully saturated. Line them up at the bottom of a serving dish (approx 25x15x5cm) to completely fill the base. Set aside.

Step 2

Put the egg yolks, vanilla and caster sugar into a large mixing bowl and beat with an electric hand mixer for 3 minutes, or until it becomes aerated, pale and leaves a ribbon from the whisks when you turn them off and pull them out of the bowl.

Step 3

Beat in the mascarpone for 3 minutes until airy (the mixture will be quite runny but don’t worry), then clean the beaters, put the egg whites into another large bowl and whisk to stiff peaks.

Step 4

Spoon a little egg white into the mascarpone mix to loosen, then carefully fold in the remaining whites in three additions, using gentle figure-of-eight motions and trying not to knock any air out. Spread half this mixture over the biscuits, then sift over 1 tbsp cocoa.

Step 5

Dip the remaining sponge fingers – you may not use all the coffee – then arrange on top of the cocoa. Spread over the remaining mascarpone mix, sift over 1 tbsp cocoa and scatter with the cocoa nibs, if using. Chill for at least 3 hours, or preferably overnight, then remove from the fridge at least 1 hour before serving, to take the chill off.