Beat together the butter, yoghurt, poppy seeds, sugar, lemon zest, salt and eggs using the whisk on a hand mixer for approx. 5 mins. until the mixture turns a paler colour. Combine the flour and baking powder, stir into the egg mixture. Transfer the mixture to the prepared cake tin.
For approx. 70 mins. in the centre of an oven preheated to 180°C. Remove from the oven, allow to cool a little, remove from the tin and leave to cool on a rack.
Mix the icing sugar and reserved lemon juice, drizzle on top of the cake.