Preheat oven to 180 degrees C. Grease and flour a 20x30cm baking tin.
In a medium bowl, stir together the flour, sugar, cocoa, bicarb, baking powder, salt and cinnamon. Add the eggs and oil, mix well. Fold in the nuts and zucchini until they are evenly distributed. Pour into the prepared tin.
Bake for 50 to 60 minutes in the preheated oven, until a knife inserted into the centre comes out clean. Cool cake completely before icing with your favourite icing.