Preheat oven to 350°F. Line a baking sheet with parchment paper or a silicone baking mat.

In a large bowl, beat the butter until smooth and almost fluffy, about 2 minutes. Add the sugars and continue beating until the mixture is light and fluffy, about 4-5 minutes. Add the eggs and vanilla and beat until smooth again.

In a separate bowl, whisk together all of the dry ingredients except the butterscotch chips. Gradually add this mixture to the wet ingredients, half at a time. Stir until fully combined.

Add the butterscotch chips and stir well.

Using a 2 tablespoon scooper drop the dough onto a baking sheet, flatten cookie dough with palm of your hand.

Bake for 10-11 minutes. Remove from the oven when cookies start to brown around the edges. Let them cool on the same tray for 5-10 minutes; this will allow them to finish baking without overcooking.

When the cookies are firm enough to handle, transfer them to a wire cooling rack and let cool completely. Serve warm or cooled. Cookies freeze well, as does the dough.