Preheat oven to 350 degrees. Line your cookie sheet with parchment paper.

In a large bowl, cream butter and sugars together until blended and fluffy.

Add peanut butter, egg, and vanilla and beat until well blended.

Slowly mix in the flour and baking soda until blended. Do not overmix.

Fold in oats, Butterfinger, and chocolate chips.

Refrigerate dough for 30 minutes.

Shape dough into balls around 2 Tbsp each. Place on prepared baking sheet.

Press each ball down slightly to flatten.

Bake at 350 degrees for 8- 10 minutes, but no longer than 10 minutes. Cookies will look underdone. Cookies will set as they cool.

Allow to cool on baking sheet for 10 minutes before transferring to a cooling rack. Makes about 2 1/2 dozen cookies.