Preheat your oven to 350°F.
In a small saucepan, melt chocolate chips with butter.
In your kitchen aid mixing bowl add eggs, sugar, oil, and sourdough starter. Whisk on medium speed for about 2 minutes.
In a separate mixing bowl, add flour, cocoa powder, baking soda, salt, and baking powder. Whisk together.
Once the melted butter and chocolate chips have cooled. Add it into the wet ingredients and whisk to create a creamy smooth mixture.
Then add in the dry ingredients to the wet ingredients and mix.
Pour the batter into a 9x13 baking pan lined with parchment paper.
Bake for 30 mins.
Remove from the baking pan, cut, and serve.