In a medium bowl, whisk the flour, baking soda, baking powder, and salt until combined. Set aside.

In the bowl of an electric stand mixer fitted with a paddle attachment, cream the butter until smooth. Add in both sugars and mix on high for 3 minutes until light and fluffy. Add the egg and egg yolk one at a time, mixing after each addition until combined. Add in the vanilla. Then stir in the pudding mix.

With mixer set on low speed, slowly add the flour mixture into the wet mixture until everything has been incorporated. Stir in chopped Hershey Cookies n' Creme chocolate and Oreos.

Cover bowl with plastic wrap and chill in the refrigerator for at least 2 hours, or up to 3 days.*

Scoop balls of chilled cookie dough onto lined baking sheet, placing them about 2 inches apart. Lightly press the top of each cookie, but don't smash them down--this will allow them to bake more evenly so you don't end up with a lump in the center. Press a few chunks of candy bar on top of each cookie dough ball, if desired. Make sure to keep dough chilled in between batches.

Bake cookies for 10-12 minutes (I took mine out at 11 minutes), or until slightly browned around edges. The centers might look underdone at first but, they will finish baking up as they cool. Allow cookies to cool on baking sheets for 5 minutes before transferring to a wire rack to cool completely.