Preheat the oven to 350°F. Lightly grease and flour a loaf pan. Set aside.
In a medium bowl, whisk together the flour, pumpkin pie spice, baking powder, baking soda, and salt.
In a large bowl, mix the pumpkin purée, granulated sugar, and brown sugar together. Beat in the eggs, then stir in the vegetable oil and vanilla extract.
Add the dry ingredients to the wet ingredients and stir until the batter is smooth. Optional: Fold in chocolate chips, walnuts, or pecans if desired.
Pour the batter into the prepared loaf pan. Smooth the top with a spatula. Bake for 55–65 minutes, covering loosely with foil after 30 minutes if browning too quickly.The bread is done when a toothpick inserted into the center comes out clean.
Let the loaf cool in the pan for 10 minutes, then transfer to a wire rack to cool completely before slicing and serving.