Melt 2 tablespoons of butter in a medium skillet over medium heat. Add 1 cup chopped pecans. Cook for about 5 minutes, stirring occasionally, until the pecans are toasted and fragrant. Remove from the heat and set aside.
In a medium mixing bowl, whisk together the bread flour, salt, and baking soda. Set aside.
In a large mixing bowl, beat together the melted butter, brown sugar, and granulated sugar until lighter in color, about 1 minute. Add in the egg, egg yolk, buttermilk, and vanilla. Mix until just combined.
Add the dry ingredients to the wet ingredients in two additions, mixing after each addition until just combined.
Using a rubber spatula, fold in the butter pecans and chocolate chips by hand until evenly incorporated into the cookie dough.
Cover the bowl and chill in the fridge for at least 1 hour. (I recommend chilling overnight for best results.)
When you're ready to bake, preheat the oven to 375 degrees F. Use a 1.5 tablespoon cookie scoop to portion the cookie dough onto a parchment paper-lined baking sheet.
Bake for 9-11 minutes or until the cookies are golden brown. Remove from the oven and let cool on the baking sheet for 2 minutes before transferring the cookies to a wire rack to cool completely.
Notes
You can use all-purpose flour instead of bread flour if desired. It's a 1:1 ratio. The cookies will have a slightly less dense and chewy texture, but they're still delicious!
Freezing Steps: Scoop the cookie dough onto parchment-lined baking sheets and place them in the freezer. Chill until firm, about 1 hour. Then transfer the dough balls to a freezer food storage bag and store in the freezer. When you're ready to make cookies, place the cookie dough balls on a parchment paper-lined baking sheet. Bake at 375 degrees F for 11-14 minutes until golden brown.