Preheat oven to 180 C / Gas 4. Grease a 20x30cm baking tin.
In a large bowl, mix together the eggs, oil, sugar and vanilla until well blended. Combine the flour, baking powder, bicarbonate of soda and salt; stir into the sugar mixture. Mix in the courgette. Spread the batter evenly into the prepared tin.
Bake for 20 to 25 minutes in the preheated oven, until a skewer inserted into the centre comes out clean. Allow cake to cool completely.
Meanwhile, make the icing. Blend the margarine, cream cheese and icing sugar together until well blended. Spread over cooled cake before cutting into slices.
Place the grated courgette in a clean tea towel and wring it out. This technique will remove much of the water in the courgette promoting a more even cook.
Think there must be a misprint! Followed recipe, but after 25 minutes the cake was nowhere near cooked, so put it back for another 25 minutes. It was STILL not cooked. Think there should be either 4oz or 125 grams sugar and NOT 400grams. Absolute disaster!!! - 09 Sep 2014