A great cake recipe for any occasion:
For the rum buttercream, also cream butter and sugar until thick. Stir in egg yolks and rum. Place the dark sponge cake base on a plate. Spread with one third of the chocolate buttercream. Place a layer of sponge cake rings on top. Start with a dark ring. Top with another light one, another dark one, and so on. Spread with half of the rum buttercream. Again a ring layer, this time starting with a light ring. Continue in this way, alternating two more ring layers on top. Spread the last one with chocolate buttercream. Top with the light-colored layer.
Allow the overture to melt. Cover the cake with it. Sprinkle with chocolate chips. Sprinkle over edge as well.
Cut into 16 pieces.