Step 1

Preheat oven to 350°F. Generously grease an 8-inch by 8-inch glass or metal baking pan.

Step 2

Combine flour, brown sugar, cocoa powder, baking soda and salt in a medium bowl.

Step 3

Combine unfed discarded starter, water, vinegar, vanilla extract and olive oil in a separate small bowl.

Step 4

Add wet ingredients to dry ingredients. Stir until moistened and pour batter into prepared pan.

Step 5

Bake for 25 to 30 minutes or until a fork inserted in the center of the cake comes out clean. Cool the pan on a baking rack.

Step 6

If frosting the cake, allow it to cool completely first.