Preheat your oven to 350°F. Butter a 9×5 bread pan generously.
In a small bowl, whisk together the flour, sea salt, baking soda, baking powder, and pumpkin pie spice. Set aside.
In a large bowl, mix the brown sugar and melted butter until creamed.
Stir in the egg, vanilla extract, sourdough starter, and pumpkin puree. Mix well, but don’t beat it to death—we’re looking for combined, not frothy.
Gradually combine the dry into the wet ingredients until just incorporated. Over-mixing can make the bread dense, and we want that light, soft crumb.
Pour the batter into the prepared bread pan and smooth the top. Bake for 60 minutes. Test the center with a knife or chopstick before removing it to make sure it comes out clean.