Preheat oven to 375 F degrees.
Combine flour, baking soda, and salt in small bowl and set aside.
With your electric mixer, beat sugar and butter until fluffy and creamy. Add in egg until just combined.
Then gradually beat in flour mixture until dough forms.
Stir in butterfinger pieces by hand. (dough will be thick)
Drop by slightly rounded tablespoonfuls onto parchment lined baking sheet.
Bake for 10 minutes or until lightly browned.
Cool and Enjoy