Preheat oven to 350°F. Add flour, salt, and baking soda to mixing bowl and sift together. Add pecans to Mix n Blend II jar and secure lid. Press "Pulse" 6–8 times.
Add chopped pecans and chocolate chips to mixing bowl with flour. Add eggs, buttermilk, butter, vanilla, and sugar to Mix n Blend II mixing bowl and secure lid. Press "Speed Up" to Speed 4; mix until creamy.
Add dry ingredients to Mix n Blend II mixing bowl. Mix at low speed until ingredients are incorporated.
Drop cookie dough onto baking sheets lined with parchment paper. Bake for 7–8 minutes, remove from oven, and carefully place marshmallows in various places on cookies.
Bake another 5–7 minutes or until golden brown, dry to touch, and slightly soft.