Preheat the oven to 375℉.
Spray a 9x5 inch loaf pan with cooking spray, then line with parchment paper. Set aside.
In a small bowl, whisk together the flour, salt, baking powder, baking soda, pumpkin pie spice, and cinnamon.
In a large mixing bowl, use a rubber spatula to stir together the butter, oil, brown sugar, granilated sugar, egg, pumpkin, and vanilla until smooth.
Add the dry ingredients and continue to stir until well mixed with no streaks of dry flour. Do not over-mix. The mixture will still be slightly lumpy.
Pour the batter into the prepared loaf pan and bake for 1 hour or until a toothpick inserted into the center comes out clean.
Allow to cool in the pan before serving. To prevent the bread from crumbling when cut, allow the bread to cool completely before cutting into approximate ¾ inch slices.