1. Heat oven to 375'F. Beat butters and sugar until fluffy. Beat in egg and vanilla. Add combined flour, baking soda and salt; mix well. Stir in oats and chocolate chips.
2. Drop by rounded tablespoonfuls onto ungreased cookie sheet. Bake 8-9 minutes for a chewy cookie, 10-11 minutes for a crisp cookie. Cool 1 minute on cookie sheet, remove to wire rack, cool, store tightly covered.