Line a baking sheet with parchment paper. In a small bowl, whisk together flour, baking soda & salt. In a medium bowl, cream butter with sugars; beat in egg & vanilla. Add flour mixture alternately with sour cream. Stir in raisins & oats.
Preheat oven to 375 F. Scoop dough onto cookie sheet a few inches apart. Bake 12-15 minutes. Allow to cool on pan about 30 seconds then remove to wire racks.