Preheat the oven to 350 degrees and line your baking sheets with parchment or a silicone liner.

In a large bowl, cream together the butter, cream cheese and brown sugar. In a small bowl, whisk together the egg, vanilla and espresso powder (if using) and add to the butter and sugar mixture, mixing well.

Sift together the flour, cocoa powder, corn starch, baking soda and salt. Fold into the butter mixture, along whit your chopped chocolate or chocolate chips, adding any additional add-ins as preferred.

Using either a cookie scoop or a tablespoon, portion out golf ball sized pieces of dough. If desired, top with additional chocolate. Bake at 350 for 10-12 minutes or until cookie looks form around the edges.