Puree banana, water and baby spinach in a strong blender.

Heat milk in a small pot over medium high heat. Add banana puree mixture of the milk. Once the milk mixture has come to a boil, add rolled oats. Reduce heat to medium. Cook for 5 minutes or until most of the liquid has been absorbed.

Remove from heat. Stir in peppermint extract. Cover the pot and let it sit for 1 minute.

Serve hot, or refrigerate and serve cold.