Preheat oven to 160°C fan forced, or the equivalent in your oven
Spray and line a rectangular loaf tin with baking paper.
Put the eggs, oil, vanilla, sugars, salt and cinnamon in a mixing bowl and whisk together until combined.
Sift in the cocoa powder, flour, and baking powder. Using a spoon or spatula, lightly fold the dry mixture into the wet mixture until combined.
Add the zucchini and mix it through.
Pour into the tin and bake for 50-60 minutes, or until a skewer inserted into the centre comes out clean.
Sit in the tin for five minutes, then turn upside down onto a rack to cool
Great to eat warm, or let it cool completely and add icing.