Pre-heat oven to 325°F.
Grease a 9 x 5-inch loaf pan and coat with flour.
In a large bowl, whisk together flour, cinnamon, pumpkin pie spice, baking powder, salt, baking soda and nutmeg.
Add walnuts and toss to coat.
In a medium bowl, whisk together pumpkin puree, oil, granulated sugar, brown sugar, vanilla and eggs until smooth.
Fold wet ingredients into dry ingredients, stirring just until dry ingredients are moistened, being careful not to over mix.
Spread batter, in prepared pan, and sprinkle sugar evenly over the top.
Bake for 65 to 70 minutes or until a toothpick inserted in the center comes out mostly clean with a few moist crumbs.
Remove from oven and allow to cool completely on a wire rack before removing from pan and slicing.
