Preheat the oven to 350°F. Lightly grease a 9x13-inch baking pan and set aside.
Prepare the dry ingredients: In a medium bowl, whisk together the flour, baking soda, baking powder, pumpkin pie spice, cinnamon, and salt. Set aside.
Combine the wet ingredients: In a large mixing bowl, beat the eggs until smooth. Add the sugar, vegetable oil, and pumpkin puree, mixing until well incorporated.
Incorporate the dry mixture: Gradually add the flour mixture to the wet ingredients, stirring until the batter is smooth and evenly blended.
Bake: Pour the batter into the prepared pan, spreading it evenly. Bake for 22 to 25 minutes, or until a toothpick inserted into the center comes out clean.
Cool: Remove from the oven and allow the bars to cool completely in the pan.