In a large bowl, whisk together quick oats, flour, cocoa powder, baking soda, salt, cinnamon, and brown sugar.
In a small bowl, whisk together butter, egg, and vanilla.
Add the wet ingredients to the dry ingredients, along with zucchini and 1 cup semi-sweet chocolate chips.
Stir until incorporated - batter will be thick and quite heavy.
Drop dough by rounded tablespoonful (golf ball-sized) onto parchment paper or silicone mat-lined baking sheets, and flatten slightly.
Press 4-5 additional chocolate chips on top.
Bake at 350 degrees for 12-15 minutes, or until centers appear set and edges are lightly browned.
Remove from heat, and allow to cool on baking sheets for 2-3 minutes before removing to wire racks to cool completely.
Store in an airtight container.