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

In a large bowl, combine the peanut butter, sugar, and egg. Stir until well combined and a thick dough forms — do not overmix.

Form small balls of dough, about 1 to 1.5 inches in diameter, and place them on the tray with space between each. Press down each ball with the back of a fork to create a crisscross pattern.

Bake for 10-12 minutes, until golden around the edges but still soft in the center.

Let the cookies cool on the tray for a few minutes before transferring to a wire rack.