Preheat oven to 350°F (177°C).
Line baking sheets with parchment paper.
Finely shred zucchini and lightly pat dry with paper towels.
In a medium bowl, whisk together flour, cocoa powder, baking soda, and salt.
In a large mixing bowl, beat butter, brown sugar, and granulated sugar until creamy.
Add egg and vanilla extract. Mix until smooth.
Stir shredded zucchini into the wet mixture.
Gradually add dry ingredients into wet ingredients and mix until combined.
Fold in chocolate chips and dark chocolate chunks.
Scoop dough onto prepared baking sheets.
Bake for 10–12 minutes until edges are set but centers remain soft.
Allow cookies to cool before serving.
