I've used zucchini in a great vegan brownie recipe.
Below is the Food.com version of their vegan zucchini brownies:
Vegan Zucchini Brownies - Yield: 24 brownies
2 cups flour
1 1/2 cups sugar
1 teaspoon salt
1 teaspoon baking soda
1/2 cup cocoa
2 tablespoons vanilla
1/2 cup oil
2 cups peeled and grated zucchini
1 Combine the flour, sugar, salt, baking soda, and cocoa in a bowl.
2 Add the vanilla, oil, and zucchini and mix well.
3 Bake in an ungreased 9 x 13 inches pan at 350 degrees fahrenheit for 30 minutes.
4 NOTE: You can substitute the sugar for splenda or add a 1/2 cup of chopped nuts if you wish.****
**** I don't use splenda - if trying to cut back on sweetener, just decrease the amount of
sugar, experimenting until you find the right amount for your taste. **********
The zucchini adds a lot of texture and moisture!