Preheat oven to 400 degrees Fahrenheit. Line a baking sheet with parchment paper, and set it aside.
In the mixing bowl of a stand mixer, cream together the butter and sugars on high for 3-4 minutes or until light and fluffy. Add the eggs one at a time, mixing well in between. Then, add the vanilla extract.
1 cup unsalted cold butter, 1 cup packed light brown sugar, 1/2 cup granulated white sugar, 2 large eggs, 2 teaspoons vanilla extract
Add the cocoa powder, cake flour, all-purpose flour, cornstarch, baking soda, and salt. Beat until just combined, making sure not to over-mix! Fold in half the chocolate chips.
1/2 cup unsweetened cocoa powder, 1 cup cake flour, 1-1/2 cup all-purpose flour, 1 teaspoon cornstarch, 3/4 teaspoon baking soda, 1/2 teaspoon salt, 1/2 cup dark chocolate chips, 1/2 cup semi sweet chocolate chips
Place the dough in the fridge for 15 minutes to chill.
Measure out 3/4 cup of dough, and roll it into a ball. (The cookies will be large!) Stuff a piece of the Hershey's bar in the center of the dough, making sure it is completely covered. Top the dough with more chocolate chips, and place it on a lined baking sheet. Repeat until all of the dough has been used, leaving approximately 2 inches between each ball of dough on the baking sheet.
3 Hersheys Cookies 'n Cream candy bars
Bake the cookies for 10-11 minutes, or until the top is dry and almost set. Remove from the oven, and cool on the baking sheet for 15-20 minutes. Then, transfer the cookies to a cooling rack to cool completely.