Preheat the oven to 350°F and brush a 9x5-inch loaf pan with oil.

In a large bowl, whisk together the mashed bananas, sugar, almond milk, vegetable oil, vanilla, and apple cider vinegar.

In a medium bowl, whisk together the flours, baking powder, baking soda, salt, cinnamon, and nutmeg.

Add the dry ingredients to the wet ingredients and stir until just combined, then fold in the walnuts. Pour into the prepared pan and sprinkle with the chopped walnuts and oats.

Bake for 42 to 50 minutes, or until a toothpick inserted in the middle comes out clean.