Preheat oven to 350 degrees F (176 C). Line a couple of cookie sheets with parchment paper or leave ungreased/un-lined.
Beat the butter and both sugars together. Beat in the peanut butter and egg; Scrape sides of bowl and beat in the salt, baking soda and vanilla. When well blended, add flour and stir until it is blended. Stir in the chips.
Shape dough into 1-inch balls (or scoop with a #70 scoop) and arrange on cookie sheets about 2 1/2-inches apart. Flatten balls with a fork making criss-cross patterns; Bake for 10-12 minutes or until slightly browned around the edges.
Makes about 3 dozen
**If you only have salted butter you can use that, but reduce the salt in the recipe to about 1/4 teaspoon.
**If you have some, try adding about 1/4 teaspoon of chipotle powder to the batter.