Combine flour, baking soda, salt and cinnamon in small bowl.
Beat butter, sugar, brown sugar, eggs and vanilla extract in large mixing bowl. Gradually beat in flour mixture.
Fold in oats and butterscotch chips.
Drop by rounded tablespoons onto ungreased baking sheets.
Bake for 7-8 minutes for chewy cookies or 9-10 minutes for crisp cookies.
Cool on baking sheets for 2 minutes; remove to wire racks to cool completely.
Notes
Before you make these cookies, be sure your butter is softened. I usually set my butter out on the counter first thing in the morning and it is ready to go in just a few hours.