Preheat oven to 350*. Cream butter and peanut butter together. Add sugars, egg, and vanilla; mix well. Sift dry ingredients together and add gradually to creamed mixture. Stir in peanut butter chips. Form dough into small balls and place on ungreased cookie sheets. Flatten slightly with a fork. Bake for 9-12 min., or until golden brown. Allow to cool for a minute, then remove from cookie sheet. Yield: Approximately 60 2" cookies.