Preheat your oven to 350 F and line a baking sheet with parchment paper.
In a bowl, mix together the peanut butter, granulated erythritol, and egg until a smooth, thick dough forms.
Scoop tablespoon-sized portions of dough and roll them into balls. Place on the prepared baking sheet about 2 inches apart.
Use a fork to press a crosshatch pattern into each cookie, flattening them to about half an inch thick.
Bake for 10 to 12 minutes until the edges are set and lightly golden. The centers will still look slightly underdone.
Let the cookies cool completely on the baking sheet. They will firm up and become perfectly chewy as they cool. Do not move them while warm or they may crumble.
