Preheat the oven to 180°C (356°F).
In a bowl, mix together the peanut butter and sugar.
Add the egg and mix well until combined.
Sift in the flour and baking powder, then mix to form a dough.
Shape the dough into balls and place them on a baking sheet.
Gently press the tops with a fork to create a pattern.
Bake in the preheated oven for 10–12 minutes.
Place on a cooling rack to cool.