Begin by combining 2 eggs, 100g butter, 100g caster sugar, 50g wholemeal self-raising flour, 50g self-raising flour and the grated zest of an orange. Pour into a lined 900g loaf tin.
Bake at 180 degrees C (160 fan) for about 40-50 mins until it is well risen and a squewer comes out clean.
Leave to cool and make the icing. Combine 75g icing sugar, 25g butter and 1 heaped tbsp thin strip marmalade.
Whisk til smooth.
Cover the cool cake with the icing and refrigerate to set.