Whisk the egg yolks and caster sugar until light and frothy in a large mixing bowl. Stir in the cream cheese until combined and set aside. Whip the cream and stir in also. In a clean bowl, whisk the egg whites until stiff and then gently fold into the mix. Add a generous spoonful of the cream mixture to each of your large serving glasses. Combine the coffee and cognac (if using) and dip a third of the sponge fingers, broken in half into it. Once they have softened slightly, place a layer over the cream in each glass. Repeat with two more layers of each. Top each with a dusting of Belbake cocoa powder and chill for several hours before serving.