• Preheat the oven to 350 degrees. Line the cookie sheets with parchment paper.
• Combine flour, cocoa, cornstarch, baking soda, and salt in a large bowl. Whisk to mix. Set aside.
• In a large mixing bowl with an electric mixer, cream together the butter, white sugar, light brown sugar until fluffy.
• Mix in the eggs, vanilla extract, and corn syrup.
• Gradually add in the flour mixture until a soft cookie dough begins to form.
• Divide the dough into 12 portions and then roll each portion into a ball using your hands.
• Place the cookie balls on a cookie sheet about 2 inches apart.
• Flatten the cookie balls into circles using the palm of your hand or the bottom of a glass (not flat, but slightly).
• Bake for 15-17 minutes until the cookies start to crack and the centers are set (not wet). Let cool before frosting.

Make the Fudge Frosting

• In a small glass bowl, microwave the heavy cream for 1 1/2 minutes or until it is boiling (or add the cream into a small pot and bring to a simmer).
• Stir in the chocolate chips and let site for a few minutes. Then stir until completely melted and smooth.
• Spoon the frosting on each cooled cookie and immediately sprinkle the rainbow coated chocolate chips on top.