Preheat the oven to 350 °F (180 °C). Prepare two large baking sheets (18-inch x 12-inch). Line them with parchment paper and oil with cooking oil spray.
In a food processor with S-blade attachment, add the cooled cooked quinoa, unsweetened cocoa powder, oat flour, peanut butter, maple syrup, and vanilla extract. Add coconut sugar if desired for sweeter cereal.
Process on medium-high speed, stopping a few times to scrape down the sides of the bowl, until it forms a sticky chocolate batter.
Lightly oil hands and roll small pieces of dough into balls. Place them on the baking sheet without touching each other. Reoil hands as needed.
Bake for 30-40 minutes at 350 °F (180 °C) on the center rack, shaking the baking sheet halfway through for even baking.
Remove from oven and cool on the baking sheet for 30 minutes until hardened.
Serve with dairy-free milk or eat as a snack.
