Preheat oven to 350.
Beat butter, sugar and vanilla together until creamy.
Add egg. Beat well.
Mix in flour, baking soda and salt until well combined.
Stir in cranberries and white chocolate.
Drop by rounded tablespoon onto ungreased baking sheets.
Bake for 9 to 11 minutes or until edges are light brown. Cool on baking sheets for 2 minutes; remove to wire racks to cool completely.