At least 6 hours before, mix the panela sugar and coffee liqueur into the espresso in a shallow bowl and set aside to cool. In another bowl, whisk the egg yolks and caster sugar together until they are very pale, thick and creamy, then whisk in the mascarpone – make sure the mascarpone is not hard or it will be lumpy when you add to the egg yolks.
Whisk the egg whites with a pinch of salt to a stiff peak and fold through the mascarpone mix. Dip half the sponge fingers, one by one, into the cooled coffee mix and lay them in an even layer on the bottom of a deep 20x40cm serving dish. Cover with a layer of the mascarpone mix. Repeat with another layer, dipping the sponge fingers into the coffee, and covering with the remainder of the mascarpone mix.
Finish with a heavy dusting of cocoa powder and allow to rest in the fridge for at least 6 hours before serving.
Recipes and photographs taken from Kitchen Table by Emily Cuddeford and Rachel Morgan, photography by Laura Edwards (Harper Collins, £25)
