Preheat the oven to 350 degrees F (175 degrees C).

Mix together peanut butter, sugar, and egg in a large bowl until well blended.

Roll dough into 24 balls; place 4 inches apart on ungreased baking sheets. Flatten each ball with the back of a fork.

Bake in the preheated oven until edges are lightly browned, about 10 to 12 minutes; do not overbake. Cool on the baking sheets for 5 minutes, then transfer to wire racks to cool completely.