Gather all ingredients. Preheat the oven to 350 degrees F (175 degrees C). Line a baking sheet with parchment paper.
Combine peanut butter, sweetener, egg, and vanilla extract in a bowl; mix well until a dough is formed.
Roll dough into 12 (1-inch) balls. Place on the prepared baking sheet and press down twice with a fork in a criss-cross pattern.
Bake in the preheated oven until edges are golden, 12 to 15 minutes.
Cool for 1 minute before transferring to a wire rack to cool completely.
