Heat oven to 375°F. Whisk flour, baking soda, and salt in a medium bowl; set aside.

Beat butter and both sugars in a large bowl until fluffy, about 3 minutes.

Beat in eggs one at a time, then vanilla.

Gradually stir in flour mixture until just combined.

Fold in butterscotch chips and optional pecans.

Drop rounded tablespoons onto ungreased sheets, about 2 inches apart.

Bake 10-12 minutes until edges are golden. Cool on sheets 2 minutes, then on a rack.