This may possibly sound a bit weird if you haven't come across it before. But the grated courgette disappears, and what it does to the cake is amazing - the texture becomes both very light and very moist. Definitely the best chocolate cake ever.
By the way, it also works beautifully as a spice cake, or lemon cake. But I only just this minute realised why all the recipes one sees are for a chocolate version - I suspect some people don't want to see little flecks of green in their cake? Personally, I quite like that and think it looks interesting....
Either way, you'll never have to worry about having a glut of courgettes again. Bring on summer!