In a large bowl (or the bowl of a stand mixer), combine the wet ingredients: pumpkin, butter, sugar, egg, and vanilla.
236 grams pumpkin purée, 110 grams melted butter, 150 grams cane sugar, 1 egg, 1 tsp vanilla extract
Beat together until combined.
Fold in sourdough starter.
240 grams ripe bubbly sourdough starter
In a second bowl, combine dry ingredients: flour, salt, and cinnamon
250 grams of all-purpose flour, 1 tsp sea salt, 1 tsp cinnamon
Add the dry ingredients to the wet ingredients and stir until combined.
Add chocolate chips if desired.
150 grams chocolate chips
Pour batter into a greased 9x5 bread pan.
Cover the dough. If you have a loaf pan with a cover, that's a great option. I use my bread box to proof this recipe since it doesn't need to be covered. Plastic wrap could work as a last resort, but I don't prefer to use it since it's not compostable. Get creative :)
Leave the dough out at room temperature for about 9 hours at 75°F (or longer if the temperature is cooler). You are looking for the batter to roughly double in volume.
Preheat the oven to 350°F (177 °C).
Bake bread for around 50 minutes. You can check the dough with a knife to see if it comes out fairly clean. If not, bake another 5 minutes and check again.
Once done, let it cool on a cooling rack for about an hour.
You can slice the bread in the pan or transfer it from the pan to a cutting surface.
Store in an airtight container. Bread will last about 5 days.