Preheat your oven to 350°F (175°C). Grease and flour a 9x5-inch loaf pan or line it with parchment paper.

In a large mixing bowl, combine the sourdough starter, pumpkin puree, eggs, vegetable oil, granulated sugar, brown sugar, and vanilla extract. Whisk until smooth and well combined.

In a separate bowl, sift together the flour, baking powder, baking soda, cinnamon, ginger, nutmeg, cloves, and salt.

Gradually add the dry ingredients to the wet ingredients, mixing gently until just combined. Be careful not to overmix.

If using optional mix-ins like walnuts, pecans, or chocolate chips, fold them into the batter at this stage.

Pour the batter into the prepared loaf pan and smooth the top with a spatula.

Bake in the preheated oven for 55–65 minutes, or until a toothpick inserted into the center comes out clean.

Remove the bread from the oven and let it cool in the pan for about 15 minutes. Then transfer it to a wire rack to cool completely before slicing.