Beat first 3 ingredients at medium speed with an electric mixer until creamy; add egg and vanilla, beating until blended.
Combine flour and next 4 ingredients; gradually add to butter mixture, beating until blended. Stir in oats and raisins. Drop by rounded teaspoonfuls 2 inches apart onto ungreased baking sheets.
Bake at 375° for 9 to 11 minutes. Cool 1 minute on baking sheets; remove to wire racks to cool. Freeze up to 6 months.