Preheat the oven to 350 degrees.
In a large mixing bowl combine the dry ingredients, the flour, cocoa, sugars, baking powder and salt. Set the dry ingredients aside.
In a medium bowl combine the wet ingredients, the cooking oil, eggs, vanilla, and starter. Mix this with a Danish dough hook or whisk until well incorporated.
Next, add the wet ingredients to the dry ingredients that are in the large bowl and mix until just combined. Don’t overmix!
With a rubber spatula fold in the chocolate chips if desired.
Grease a 9”x13” pan, we prefer using a Nordic aluminum pan for best results, but you can use a glass pan as well. If using glass, make sure to lessen the oven temperature to 325 degrees and increase the bake time by 5-10 minutes as they will bake up slower in a glass dish.
Spread out the brownie batter into the prepared pan. It will be thick in consistency.
Place the pan in the preheated oven and bake for 24-28 minutes.
Remove to a wire rack and let cool for 20 minutes before cutting into the brownies! Enjoy!!