Preheat oven to 410℉. Prepare a large baking sheet with parchment paper or non-stick spray, set aside.

In a medium bowl add in cocoa, cake flour, all-purpose flour, cornstarch, baking soda, and salt.  Whisk together and set aside.

In a large mixing bowl, with a hand mixer or a stand mixer, cream together butter, light brown sugar and granulated (white) sugar on high speed until light and fluffy (about 3-4 minutes). Add eggs one at a time, mixing well after each addition and scraping the sides of the bowl until all incorporated.

With the mixer on low speed, slowly add in the dry ingredients to the wet ingredients until dough is formed.  Chop up the semi-sweet chocolate bar into chunks.  Add chocolate chunks, milk chocolate, dark chocolate and white chocolate chips to the batter.  Mix until fully incorporated.

Chill cookie dough in the refrigerator for 30-45 minutes.

Scoop out cookie dough in round shapes and place on prepared cookie sheets.  You can add more chocolate chips on top if you desire.  Bake for 10 minutes.  You only want the sides to look baked and tops look undone.  You DO NOT want to overbake.  Cookies should look not done and should still be soft.  Allow the cookies to cool on baking sheet for 15 minutes before removing and placing on a wired rack.  This will give cookies time to set and not break apart when you move them.