Preheat the oven to 160 °C. Grease the cake tin with butter, line with baking paper. Lightly grease the baking paper.
Beat the butter with the brown sugar in a mixing bowl for about 5 minutes until light and airy. Add the eggs one by one. Beat well. Only add the next egg when the previous egg has been fully incorporated. Beat for another 2 minutes. Sieve the flour and the baking powder and a pinch of salt over the bowl and spoon as lightly as possible through the cake mixture. Finally, fold the milk and the poppy seeds though the mixture.
Bake the mixture in the middle of the oven for about 50 minutes until golden brown and cooked. To check if your cake is cooked, insert a clean (wooden) skewer into the centre of the cake and remove it. The cake is ready if the skewer comes out clean. Cool on a wire rack.
For the frosting, beat the egg whites until stiff with the mixer and add the icing sugar. Add a few drops of food colouring until you have a nice pink colour.
Cut off the top of the pomegranate. Cut through the shell at the segments and break the fruit open. Remove the seeds. Roughly chop the pistachio nuts.
Cover the cooled cake with the frosting. Sprinkle with the pistachios and pomegranate seeds to decorate.
Tip: Prefer not to use food colouring? Collect the pomegranate juice and use this to colour the frosting. It will turn pale pink. For a deeper pink, use a teaspoon of beetroot juice.
