Cream butter, sugars, salt, and vanilla until very fluffy. Separately, whisk together remaining dry ingredients then slowly beat them into the butter mixture until just combined. Stir in chocolate chips. Shape dough into two 1 1/2" wide logs, saran wrap and refrigerate 3 hours (to 3 days). Preheat oven to 325 °F. Line baking sheets. Bake 1/2" thick slices 12 minutes.