Preheat your oven to 350°F (175°C).
Line a baking sheet with parchment paper or a silicone baking mat.
In a medium mixing bowl, combine the peanut butter, sugar, and egg. Stir until the mixture becomes smooth and fully combined.
Roll the dough into 1-inch balls and arrange them on the prepared baking sheet, leaving about 2 inches of space between each cookie.
Using the back of a fork, gently press each dough ball to create the classic criss-cross pattern.
Bake for approximately 12 minutes, or until the edges are lightly golden while the centers remain soft.
Allow the cookies to cool on the baking sheet for 2 to 3 minutes before carefully transferring them to a wire rack to cool completely.
Serve and enjoy.