Preheat the oven to 350-degrees. In a large mixing bowl beat the butter on medium speed until creamy, about 1 to 2 minutes.
Add the sugar and continue beating for another 2 minutes until the butter and sugar are blended and fluffy.
Drop in the eggs one at a time, mixing for about 30 seconds after each to blend into the butter and sugar.
In a small bowl whisk together the flour, baking soda, kosher salt, cinnamon, cocoa powder, and the chopped bittersweet chocolate.
Add the flour and chocolate mixture to the butter and sugar, mixing in on low speed until blended together, about 1 to 2 minutes. Scrape the dough down on the sides and bottom of the bowl.
Stir in the vanilla extract, blending on low for another minute.
Stir in the oats, pecans, and chocolate chips on low speed to combine evenly into the dough.
Drop rounds of cookie dough – about 1” each – onto a baking sheet lined with a Silpat liner or parchment paper. Leave about 2” between cookies.
Bake in a 350-degree oven for 8 to 10 minutes until the cookies are set but still soft in the middle. Cool on the pans for about 3 to 4 minutes then transfer to a wire rack to cool completely.