Preheat the oven on 180°C and grease a nine-inch cake tin. Line the bottom with baking paper.
Blend the sugar, eggs and oil.
Sift flour, salt and cinnamon and fold through with nuts and zucchini.
Pour mix into prepared tin and bake for one hour or until a skewer comes out nice and clean. Cool.
For the icing, beat the butter with the icing sugar and add lemon juice and the zest. Using a spatula smear the icing over the top of the cake and serve.