Pour the milk and water into a medium saucepan. Heat on high heat. Watch the liquid carefully and turn the heat to medium when the liquid starts to boil.
While the liquid is heating, add walnut pieces to a small saute pan on medium heat and toast for about 2 to 3 minutes.
When the liquid in the saucepan just reaches a boil, turn the heat down to medium and add the oats and flax seeds. Stir, and cook for 4 to 5 minutes.
Add the coconut sugar, bananas, butter (if using), and cinnamon to the walnuts, stirring occasionally until the sugar melts.
If not using butter, add the walnut banana mixture to the oats and stir.
If using butter, serve the oats in bowls and top the oats with the walnut banana mixture/glaze.
Drizzle honey on top if desired.