Preheat oven to 350 degrees Fahrenheit (177 degrees Celsius).

Grease a 9×5” loaf pan and set aside.

In a small bowl, mix together flour, pumpkin pie spice, cinnamon, baking powder, salt, and baking soda. Set aside.

In a large bowl, whisk together pumpkin puree and melted butter.

Add brown sugar and granulated sugar and stir until combined and there are no lumps.

Add eggs and vanilla and stir to combine.

Add dry ingredients and stir until batter is smooth.

If desired, add mix-ins like chocolate chips, cinnamon chips, or walnuts and stir until evenly distributed.

Pour batter into prepared loaf pan and use a spatula to smooth out the top.

Bake in the preheated oven for 60-65 minutes, or until a cake tester inserted into the center of the loaf comes out clean.

Let pumpkin bread cool in the loaf pan on a wire rack for at least 1 hour before removing it, or overnight.