01 -
Preheat oven to 350°F (175°C).
02 -
In a large mixing bowl, cream together butter, sugar, and brown sugar for 3-4 minutes until light and fluffy.
03 -
Add eggs one at a time, mixing well after each addition, then add vanilla.
04 -
Stir in flour, cake flour, cocoa powder, and salt until combined.
05 -
Fold in semi-sweet chocolate chunks or chips.
06 -
Pour batter into a 9 x 13-inch baking pan and spread evenly.
07 -
Bake for 28-36 minutes, or until a toothpick inserted in the center comes out with crumbs but not wet batter.