Preheat the oven to 170°C (338°F).
In a bowl, mix peanut butter and sugar together.
Add the egg and mix thoroughly.
Sift in the all-purpose flour and salt, then knead to form dough.
Shape the dough into balls and place them on a baking tray.
Gently press the surface with a fork to create a pattern.
Bake in the oven for 12 minutes.
Allow to cool before serving.