Preheat your oven to 350°F (175°C).

In a mixing bowl, combine the peanut butter, sugar, egg, and vanilla extract until smooth.

Mix until all ingredients are well incorporated, and the dough is consistent.

Using a tablespoon or cookie scoop, portion out the dough and roll into balls.

Place the dough balls on a baking sheet lined with parchment paper, spacing them about 2 inches apart.

Flatten each ball gently with a fork, creating a crisscross pattern on top.

Sprinkle a little granulated sugar on top of each cookie before baking.

Bake in the preheated oven for 10 minutes or until the edges are lightly golden.

Remove from the oven and let the cookies cool on the baking sheet for 5 minutes before transferring them to a wire rack to cool completely.