Add peanut butter, sweetener, egg, vanilla, and salt to a mixing bowl.

Stir until the mixture is smooth and forms a thick, uniform dough.

Divide the dough into 12 equal portions and roll each portion into a ball.

Place the dough balls on the prepared baking sheet with space between them.

Press each ball gently with a fork in one direction, then again in the opposite direction to create a crisscross pattern.

Bake for 10–12 minutes, until the edges look set and lightly golden but the centers are still soft.

Remove the tray from the oven and let the cookies cool completely on the baking sheet before handling