Preheat the oven to 180°C and grease a 900g loaf tin with butter and parchment.
Cream the sugar and butter in a bowl until pale and fluffy.
Add eggs one at a time, beating well between each addition.
Fold in the flour, salt, and grated citrus zests.
Pour batter into the tin and bake for 1 hour, covering with foil after 40 minutes if browning.
Verify the cake is cooked when a skewer comes out clean and let cool in the tin.
Prepare syrup by heating 100ml water, caster sugar, and citrus rind strips until dissolved and translucent.
Brush the syrup over the warm cake and let it cool completely before removing from the tin.
Mix icing sugar with citrus juices to create a thin icing.
Drizzle icing over the cold cake and garnish with reserved rind strips.