Preheat the oven to 350°F (180°C). Spray a 9x13 pan with non-stick spray and set aside.
Using a stand mixer, cream together the butter and sugars until light in color and fluffy in texture. You can also use an electric hand mixer, if you’d like.
To the butter + sugars, add in the eggs, corn syrup and vanilla. Mix until thoroughly combined.
Next, add the flour, cocoa, corn starch, baking soda and salt. Mix until your chocolate cookie dough forms. The dough will be soft.
Press half of the dough into the bottom of the prepared pan.
Pour and spread the hot fudge sauce on top of the cookie dough.
Crumble the remaining cookie dough onto the top of the hot fudge layer.
Bake at 350°F (180°C) for 17-20 minutes.
Allow the cookies to cool completely before sprinkling with powdered sugar. Cut and enjoy!
