Place all ingredients, except for banana and maple syrup into pint sized jar or container. Give the ingredients a good stir, to fully mix together. 

Once mixed together, add banana slices. Drizzle with maple syrup, if using, (maple syrup is optional, use if a sweeter taste is desired) to jars. Stir. Once ALL ingredients are mixed together, add additional milk (if desired) to loosen up the oats a bit, then stir well, to blend.

Cover jars with plastic wrap, and refrigerate overnight.  When ready to serve, garnish with additional banana slices (if desired).  Oats will keep for 2-3 days when stored tightly covered in refrigerator.