Preheat the oven to 350℉/176℃ and line two baking sheets with parchment paper.
Add everything EXCEPT the optional ingredients to your food processor and process until smooth.
OPTIONAL: Add the spinach AND additional ¼ cup rolled oats and process until smooth. (The spinach adds more moisture, so the extra oats are needed.)ORAdd 25-30 drops of green food dye, and pulse a few times to mix through.
Use a small cookie scoop to scoop the batter onto your baking sheets. You'll get about 26 cookies. Then use slightly wet hands or the back of a spoon to press the cookies down and shape them into rounds. The batter won't spread much, so shape them before baking.
Bake for 16-18 minutes, then remove from the oven and gently press the candy eyes (if using) into your cookies while they are still warm. Then let them cool.
Notes
For green cookies:
The cookie batter is very beige in colour so you'll need a fair bit of food colouringOR spinach to get them green. CHOOSE ONE OPTION. For food dye-free, stick to the spinach option.
For the spinach option, (my preferred choice) you need the extra ¼ of oats to balance the additional moisture from the spinach. (YOU WON'T TASTE THE SPINACH.)
Additional Tips:
Use VERY ripe bananas that are spotted brown, since there's not much added sweetness.
If using the candy eyes, make sure to press them into your cookies, immediately after removing them from the oven, while they are still warm.
These cookies are naturally vegan, but most food colouring is not. If you need these to be vegan, make sure to choose vegan food colouring, OR use the spinach option.