Preheat your oven to 350°F (175°C). Line a baking sheet with parchment paper.

In a bowl, mix the peanut butter, sugar, egg, and vanilla extract (if using) until combined.

Scoop the dough into small balls. Place them on the baking sheet and flatten each ball with a fork, creating a crisscross pattern.

Bake for 10 minutes, or until lightly browned.

Cool on a wire rack before devouring these nutty delights!