In the bowl of a stand mixer, place cooled toasted butter, brown sugar and white sugar. Using a paddle attachment, mix on medium high speed for 1 minute until smooth. Add in the eggs and egg yolks and mix again for 1 minute. Add in the vanilla and mix until incorporated.
In a separate bowl, whisk together the flour, cinnamon, cornstarch, baking soda, salt and baking powder. Add the flour mixture into the wet mixture and stir on medium speed for a minute or until the flour is just incorporated. Fold in the pecans and toffee bits.
Once the cookie dough is made, cover the surface with plastic wrap and place it into the fridge for at least one hour and up to 24 hours.
Once the dough has chilled, remove the bowl from the fridge. Preheat the oven to 350 F. Line a baking sheet with parchment paper.
Using a cookie scoop for even sizing, scoop a ball of dough. Form it into a disc. Space the cookies at least an inch apart. I was able to fit 6 cookies onto the baking sheet. Sprinkle the tops of the dough discs with toffee bits and a couple of pecan halves. Place into the oven to bake for 13-15 minutes or until the edges have turned a golden brown and the center is baked.
Remove from the oven and let cool for 5 minutes before serving.
Notes
Storage: Cookies may be stored in a baggie or airtight container at room temp for up to a week.