1) Preheat the oven to 350°F. Lightly grease a 9" x 5" loaf pan.
2) In a large bowl, mash the bananas, then add the oil, sugar, eggs, milk, and vanilla, stirring to combine.
3) Mix in the flours, baking soda, baking powder, salt, and chopped walnuts. Scrape the bottom and sides of the bowl to thoroughly combine the ingredients.
4) Scoop the batter into the prepared pan. Mix together the sugar and cinnamon, and sprinkle over the batter.
5) Bake the bread for about 60 to 75 minutes, until a cake tester or toothpick inserted into the center comes out clean. If the bread appears to be browning too quickly, tent it with aluminum foil for the final 15 to 20 minutes of baking.
6) Remove the bread from the oven. Cool it in the pan for 10 minutes, then turn out of the pan onto a rack to cool completely.
Yield: 1 loaf, 18 slices.