Preheat the oven to 410. Prepare two baking sheets lined with silicone mats or parchment paper.
Cream together the cold, cubed butter and both sugars for approximately 3 minutes. (I use my KitchenAid mixer with the paddle attachment.)
Beat in the eggs, one at a time, scraping down the sides in between and add in the vanilla.
In a separate bowl, whisk together the flour, cocoa powder, cornstarch, baking soda and salt.
Add the dry ingredients to the creamed butter, sugar and egg mixture and mix on low until just combined.
Mix in the chocolate chips, caramel pieces and pecans in to the dough, (you can leave some out to press in to the cookies if desired.)
Using a large cookies scoop, separate the dough in to 12 equal size balls of dough, yes they are HUGE.
Mix together the reserved pecans and chocolate chips and dip the top of each ball of dough lightly in the mix ins before placing six balls of dough on each cookie tray. Push two of the caramel pieces in to the top of each and use your fingers to make them tall again if necessary – (don’t be afraid to get your hands dirty – just make sure they are clean first!)
Bake for 10-11 minutes until the cookies are just crisp on the top. They will still be beautifully gooey inside. (For best results I cook one tray in the oven at a time on the middle shelf.)
Remove from the oven and let the cookies sit on the trays on a cooling rack for 10 minutes, then transfer the cookies to the cooling racks. Let cool at least another 10 minutes before eating so they set.