Start with marinating the prunes a day in advance if you can . Place the prunes in a bowl or a small pan, pour in the alcohol of your choice, cover with cling film or a lid and leave to marinate overnight.
Now start gently simmering the prunes in a small pot until the alcohol evaporates.
Whisk all the remaining ingredients together by using an electric mixer or even a blender.
Leave in the fridge to rest (covered with cling film) for 1-3 hours.
Take it out of the fridge a few minutes before baking and whisk it again to create a light frothy texture.
Heat the oven to 190-200 C, grease a round baking dish very well and dust with flour.
Spread the prunes on the bottom of the baking dish and start slowly pouring in batter. It should cover or almost cover all the prunes.
Bake in the preheated oven for 40-50 minutes, the centre of the cake should still be slightly soft when you touch it and the edges a dark golden colour, but not burnt.
Serve warm dusted with icing sugar.