Preheat the oven to 375 degrees Fahrenheit, and line a baking sheet with parchment paper.
In a mixing bowl, combine the wet ingredients: zucchini, carrot, spinach, apple sauce, flax egg and maple syrup. In a separate bowl, combine flour, cocoa powder, oats, salt and baking soda. Mix the wet with the dry until you have a batter with consistent texture all the way through. Carefully fold in the chocolate chips.
Using a tablespoon or cookie scoop, create 8-10 even cookies on your baking sheet. These will not spread far, so make sure you press them down into a flat cookie shape before placing the baking sheet in the oven.
Bake for 12 minutes, until your cookies are slightly firm. Remove from the oven, and allow to set for at least 10 minutes before eating.