Reciprocal Cookies (Peanut Butter)

This is an old recipe from the King Arthur 200th Anniversary Cookbook. I’ve made these cookies many times. Typically I make only the the chocolate cookies with peanut butter chips, but I love the math reference in the recipe title!


  • ½ cup (1 stick) butter
  • ½ cup chunky peanut butter
  • ½ cup sugar
  • ½ cup brown sugar
  • 1 egg
  • 1¼ cups (162 grams) unbleached all-purpose flour
  • ½ teaspoon baking powder
  • ½ teaspoon baking soda
  • ¼ teaspoon salt
  • 1 cup chocolate chips optional
  • granulated sugar to sprinkle on top optional


  1. Cream the butter, peanut butter and sugars until light. Add the egg and mix until fluffy.
  2. Blend the flour, baking powder, soda and salt together well. Add these dry ingredients to the butter mixture. Add the chocolate chips, if using, and mix well. Cover and chill for an hour to make the dough easier to handle.
  3. Preheat the oven to 375°F.
  4. For reciprocal cookies, drop by teaspoonfuls onto greased cookie sheet.
  5. For traditional peanut butter cookies, roll the dough into 1-inch balls between your palms, and place 2 inches apart on a lightly greased cookie sheet. Use a fork to flatten with a crisscross pattern. Sprinkle with sugar if desired.
  6. Bake 10 to 12 minutes.