Preheat oven to 350 degrees and coat a 9×13 inch baking pan with non-stick spray. Whisk together flour, cocoa powder, sugar, baking powder, baking soda and salt.
Add buttermilk, eggs and oil and mix well until combined. Stir in extract. Pour into prepared pan and bake about 25 minutes or until a toothpick inserted into the center comes out clean.