Put 6 yolks in a bowl and beat them with sugar until they are creamy and frothy. Add the Mascarpone and a shot of liqueur. Incorporate 6 whipped eggs. Put the coffee in a bowl and mix it with a bit of sugar and the remaining liqueur. Spread the bottom of a Pyrex dish with the Mascarpone cream and lay over the Sponge Fingers soaked in the coffee. Cover them with another layer of cream, then another layer of sponge fingers finishing with the cream. Put the Pyrex in the fridge for at least 2 hours. Sprinkle over the cocoa powder before serving.