Ingredients:

1 c - butter or margarine
1 1/2 c - light brown sugar, packed
1 1/2 c - creamy peanut butter
1 - egg
2 ts - vanilla extract
2 c - unbleached all purpose flour
1 ts - baking soda
1 c - chocolate chips

Method:

In a large mixing bowl, cream the butter and sugar until light and fluffy.
Beat in the peanut butter, egg, and vanilla, blending well.
Thoroughly blend the flour and baking soda. Gradually add to the creamed mixture.
Fold in the chocolate chips and refrigerate the dough for at least 1 hour.
Preheat the oven to 350 degrees F.
Shape the dough into 3/4-inch balls and place on ungreased cookies sheets 3 inches apart.
With the bottom of a glass, press each ball into a cookie 1 1/2-inches in diameter.
Bake for 15 to 20 minutes or until lightly brown.