Coat the bottom and sides of a 6-quart slow cooker with butter. Add quinoa, oats, amaranth and flax seeds to slow-cooker insert. Pour in milk and water. Whisk together until well blended. Add sugar, butter, vanilla and spices. Stir to combine. Cover and cook on low heat for 6 hours. Remove lid and scoop one cup into bowls, pour warm cream or milk over top, add chopped nuts, fresh seasonal berries and a drizzle of maple syrup if desired.