Preheat oven to 160ºC. Grease and line a loaf tin.

Pour poppy seeds into a small bowl and add milk. Stir and set aside to soak.

Beat butter and sugar until pale and creamy. Add eggs one at a time, beating well between each addition. Add half of the orange rind and half the lemon rind and stir to incorporate.

Sift in flour, then add sour cream, orange juice and the poppy seeds and milk. Mix gently to combine.

Put batter into prepared loaf tin and bake for 40 to 45 minutes or until a skewer inserted comes out clean.

Cook in tin for 15 minutes before turning out to cool on a wire rack.

To make the icing, combine lemon juice and icing sugar and stir with a fork until smooth. If more liquid is required add water or extra lemon juice.

Spread icing over cake and garnish with remaining orange and lemon rind.