Step 1

Mix pumpkin puree, milk and sourdough starter together in a bowl.

Step 2

In another bowl, beat the butter (or oil) and sugar together until light and fluffy. Add in the vanilla extract and eggs and mix until well combined.

Step 3

Add the pumpkin puree mixture to the butter and sugar mixture and mix until all incorporated.

Step 4

Add the baking powder, baking soda, pumpkin pie spice and mix well. Slowly add in the flour and mix until just combined, without overtaxing. For a long ferment, cover well and refrigerate for 1-3 days.

Step 5

Preheat oven to 350°. Pour batter onto an oiled or parchment paper lined baking sheet and bake for 20-30 minutes or until a toothpick comes out clean. Let cool before frosting.