- Preheat oven to 325°F. Prepare cookie sheets with parchment paper. 
- Using a grater, finely grate a medium sized zucchini. This should yield about 2 cups of zucchini. Place zucchini in a clean dish towel and squeeze vigorously, removing most of the liquid. You should now have about 1 cup of drained shredded zucchini. Set aside. 
- In a microwave-safe bowl, melt the semi-sweet chocolate chips for 30 seconds. If chips are not melted, return to microwave in 10-second increments until mostly melted. Stir frequently. When melted, set aside. 
- In a medium bowl, add flour, cocoa, baking soda, and salt. Sift together with a whisk. Set aside. 
- In a stand mixer or bowl with a hand mixer, add in butter and sugars. Mix for about a minute, or until mixture is fully combined and starts to fluff. 
- With a stand mixer (or hand mixer on low), add in egg and vanilla. Combine fully. 
- Pour in melted chocolate and mix completely. 
- Add flour mixture to chocolate mixture and mix on low speed until just incorporated. 
- Remove bowl from stand mixer (or remove hand mixer) and fold in zucchini and milk chocolate chips by hand. 
- With an ice cream scoop (or large spoon) drop balls of dough onto a cookie sheet, about 8 per sheet. Leave 2-inches between each ball of dough. (I did not flatten cookies at any point) 
- Bake for 10-12 minutes. 
- Remove from oven and let sit on the pan for 5-10 minutes before transferring cookies to a cooling rack.