1. Heat oven to 350°F.
2. Beat butter, sugar and peanut butter in large bowl until creamy. Add egg and vanilla; beat well. Stir together flour, baking soda and salt; gradually add to butter mixture, beating until well blended. Stir in peanut butter chips; drop by scant 1/4 cupfuls onto ungreased cookie sheet, 6 cookies per sheet.
3. Bake 12 to 16 minutes or until lightly browned around edges. Cool 1 minute; remove from cookie sheet to wire rack. Cool completely. Makes about 18 cookies.