Preheat the oven to 350°F and grease two 8-inch round cake pans; line the bottoms of the pans with parchment paper - this cake is very moist, and it will make removing them much safer.
In a blender, combine the milk, eggs and vanilla; add the cooked quinoa and the melted butter and blend until smooth. In a medium bowl, whisk together the sugar, cocoa, baking powder, baking soda and salt; add to the blender and pulse until well blended.
Divide the batter evenly between the pans and bake for 40-45 minutes or until a knife inserted in the center comes out clean. Remove from the oven and cool completely in the pans before running a thin knife around the edges and inverting them onto plates. Frost if you like, or serve dusted with icing sugar.