1. Preheat oven to 350°.
2. Beat together butter and sugars at high speed with an electric mixer until smooth and creamy. Stir in vanilla and egg.
3. Lightly spoon flour into a dry measuring cup; level with a knife. Sift together flour and next 3 ingredients. Add to butter mixture, beating well. Stir in remaining ingredients.
4. Drop by level tablespoonfuls 2 inches apart onto parchment-lined baking sheets.
5. Bake at 350° for 12 minutes or until golden brown. (Cookies will be slightly soft in center.) Cool for 3 minutes on baking sheet before removing to wire racks.