In a large bowl add brownie mix and whisk to eliminate any lumps that might be in the mix.  Add whisked eggs, vegetable oil and flour.  Mix until well combined and set aside.

In a large bowl add yellow cake mix and whisk to eliminate any lumps that might be in the mix.  Add whisked eggs, vegetable oil and flour.  Mix until well combined.  Add chocolate chips and mix until evenly incorporated.

Preheat oven to 350 degrees.  Using a medium cookie scoop, get an even mound of each dough.  Roll both doughs in your hand, being sure to keep the cookie half and half, until you get the right shape.  NOTE:  The dough might seem oily but it won't bake up that way.  Place 6-8 cookies on a parchment or Silpat lined baking sheet.  Bake your brookies for 10-12 minutes. 

Remove your brookies from oven and let them set on cookie sheet for 10 minutes.  This will allow cookies to cool and set up.  Don't skip this step, it is very important.  Continue until all of your cookies are baked.  Store in an airtight container at room temperature for up to 5 days.  Freeze for up to 3 months.