Preheat the oven and prepare baking trays: Preheat the oven to 180°C (350°F). Line two large baking sheets (approximately 45cm x 30cm / 18in x 12in) with parchment paper.
Blend the ingredients: In a food processor, add the cooked quinoa, coconut sugar, cocoa powder, oat flour, peanut butter, maple syrup, and vanilla extract. Blend for 2 minutes until a sticky chocolate batter forms, scraping down the sides of the bowl as needed.
Shape the cereal balls: Lightly oil your hands, take small pieces of dough, and roll them into small balls. Place them on the prepared baking sheets, ensuring they do not touch. If the dough becomes too sticky, wash and dry your hands, then re-oil before continuing.
Bake the cereal: Place the baking sheets on the centre rack of the oven and bake for 30–40 minutes, shaking the tray halfway through to ensure even baking on all sides.
Cool and harden: Remove the baking sheets from the oven and allow the cereal to cool for 30 minutes. The pieces will harden as they cool.
Serve: Enjoy with any dairy-free milk or eat as a crunchy snack on its own.