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

In a medium mixing bowl, combine the peanut butter and egg, stirring until well blended and smooth.

Gradually add the flour to the peanut butter mixture, stirring until a cohesive dough forms.

Using your hands or a small cookie scoop, roll the dough into 12 equal balls and place them on the prepared baking sheet.

Using a fork, gently press down on each cookie ball to create the classic crisscross pattern, flattening them to about 1/4-inch thickness.

Bake for 10-12 minutes, or until the edges are lightly golden and the centers appear set.

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

Allow cookies to cool completely before serving or storing.