Three-Ingredient Peanut Butter Cookies Gain Popularity

• Versions of the three-ingredient cookie recipe, using just peanut butter, sugar, and egg, have been around for decades.
• The absence of butter and flour results in a purely peanutty flavor.
• The recipe is not overly sweet, though some versions call for double the sugar.
• The cookies are best made with white sugar and conventional peanut butter.
• The simplicity and flavor of the recipe are the main reasons for its enduring popularity.