First, combine flour, baking soda, baking powder, salt, cinnamon, and pumpkin pie spice in a bowl and set aside.
Next, in a large mixing bowl, add in brown sugar, eggs, active sourdough starter, butter, milk, vanilla, and pumpkin puree. Mix until just combined. Do not over mix.
Add your mix ins such as chocolate chips, nuts, or dried fruits. This step is optional.
Fill a greased or lined muffin tin about 3/4 full in each cup. Bake at 375 degrees for 18-20 minutes or until a tooth pick comes out clean. Let cool on a wire rack for several minutes before servings. You can store these in an airtight container at room temperature for 4 days or you can freeze for longer storage. Enjoy!