Mix all the ingredients together and store in an airtight container. Serve with milk and/or plain Greek-style yogurt and a trickle of honey, if desired.
For a hot breakfast, mix 1/2 cup of the cereal with 1/2 cup milk in a saucepan. Bring to a boil, then reduce the heat and simmer gently, stirring occasionally, until thick and creamy, about 3 minutes.