Preheat the oven to 350 degrees (F). Line a baking sheet with parchment paper.

Beat together sugar, peanut butter, egg, and vanilla extract until thoroughly combined.

Using a tablespoon, scoop out dough and roll it into balls.

Place the balls of dough on the prepared baking sheet 2 inches apart. Use a fork to press a crisscross pattern in the dough.

Bake for 10 - 12 minutes.

Cool on a baking sheet for 5 - 10 minutes.