A while back, my friend had given me a giant zucchini. I put half of it in the blender and ended up with 4 cups of zucchini puree. I froze it in 2 cup portions. I tried this recipe for zucchini cookies from sixsistersstuff.com.
Here's the recipe: http://www.sixsistersstuff.com/2013/07/iced-zucchini-cookies-recipe.html
I followed the recipe pretty close except I didn't have vanilla so I just omitted that. And I used zucchini puree instead of grated zucchini. The dough was more the consistency of a cake mix probably since there was more liquid with the pureed zucchini so I poured it into two round cake pans instead of making cookies. When the cakes cooled, I spread the icing around the top. These turned out great!
After Big Ripples asked for seconds, I told her there was zucchini in it. She stopped eating and was like "really?!". She wasn't sure if she should believe me and hesitated eating the rest, so I told her I was just kidding and there wasn't zucchini in it. She happily finished eating her cake. Just a little white lie. :)