Melt 8 oz of the chocolate in the microwave by heating at 50% power and stirring every 30 seconds until fully melted. Set aside.
Combine flour, cinnamon, baking powder, corn starch, cocoa powder, and salt in a small bowl.
Cream butter and sugars together in a large mixing bowl.
Add eggs on at a time and beat until well combined.
Beat in vanilla.
Add melted chocolate to the mixer and continue beating until well combined.
Slowly add flour mixture and stir just until combined.
Stir in remaining chocolate chips.
Refrigerate cookie dough for AT LEAST one hour.
Preheat oven to 375 degrees.
Drop cookie dough by rounded tablespoons onto a parchment lined cookie sheet.
Bake for 8-10 minutes or just until cookies are slightly cracked on top. Transfer to a wire rack and let cool slightly.
Enjoy!