Preheat oven to 350°
Grease a 9 x 5" loaf pan with butter and lightly dust with flour.
Sift flour, baking powder, baking soda, salt, pumpkin pie spice, and granulated sugar in a large bowl.
Whisk the light brown sugar, room temperature eggs, oil, and canned pumpkin in a medium bowl.
Add the wet ingredients to the dry ingredient and whisk until smooth.
Pour the batter into the prepared loaf pan.
Bake for 30 minutes. Cover with aluminum foil and continue baking for 30-40 minutes, until a toothpick inserted into the center comes out clean.
Allow to cool slightly in the pan, and then cool completely on the counter before serving.