Preheat the oven to 350 degrees. In a small mixing bowl, combine the flour, cocoa powder, baking soda, and salt. Set aside.
Add the butter, granulated sugar, and brown sugar to a large mixing bowl. Using a hand mixer, cream together the butter and sugars for 2 minutes, or until creamy and smooth.
Add the vanilla extract and the egg to the butter mixture and mix for 2 minutes, or until creamy and smooth. Stir in the zucchini. Set aside.
Melt the unsweetened chocolate In a medium sized microwave safe bowl, doing so in 30 second intervals until the chocolate is smooth and creamy.
Add the melted chocolate to the wet batter and stir to combine.
Stir in the flour mixture and stir until the flour is just incorporated into the cookie dough.
Add the white chocolate chips and stir until evenly distributed.
Portion the cookie dough by 1 tablespoon sized portions onto a parchment lined cookie sheet.
Bake for 13 minutes, or until cookies no longer look wet and bounce back when lightly touched. Cool and store in an airtight container.
Video
Notes
Tips And Substitutions
Always pre-shred, salt, and drain the zucchini first. This removes excess moisture from the zucchini and prevents the baked good from being soggy.
Try to use small to medium sized zucchini (no bigger than 6 inches long). The large the zucchini gets, the more likely it will be bitter.
If the zucchini has large seeds, remove the seeds before shredding.
Substitute 1 cup shredded apple for the zucchini.
Substitute semi-sweet chocolate chips for the white chocolate.