Start by browning the butter. You'll take 14 tablespoons of butter, (using the other 2 tablespoons from the stick to toast the pecans), and melt in a medium saucepan, and then continue to cook past the point of boiling. You will do this over medium heat, past the point of the butter foaming, until it turns a nice golden brown, and has a nutty smell. Make sure you are stirring and watching it, because it will turn from perfectly brown to burnt fairly quickly. Once finished browning, pour into a cup or bowl and allow to cool slightly while you toast the pecans.
Place 2 tablespoons of butter and 1 cup of chopped pecans in a small sauce pan and toast over low-medium heat for 5-8 minutes until nice and toasty. Set aside to cool while preparing the cookie dough.
Place browned butter and sugars in the bowl of a stand mixer, fitted with a paddle attachment. Beat on medium-high speed until light and fluffy, 2 to 3 minutes.
Add egg, yolk and vanilla, mix until smooth on low speed, about 30 seconds.
Add flour, soda, salt, cinnamon and mix until combined. Fold in the cooled pecan pieces. Scoop the dough into large balls. I like to use a 3 tablespoon cookie scoop for these. Refrigerate the dough for 2-24 hours.
Preheat oven to 350 F. Line two baking sheets with parchment paper.
Place 6-8 cookie balls on your baking sheet and sprinkle with flaked salt and an extra pecan if wanted. Bake the cookies for 10-12 minutes. You're looking for a light golden brown outside rim. Sprinkle with more salt if you like.