Preheat the oven to 180°C.
Cream together the butter and sugar in a bowl.
Add the egg and mix well.
Add the flour and baking powder, then mix.
Add the Nutella and blend into the dough.
Shape the dough into balls and place on a baking tray.
Bake in the oven at 180°C for 12-15 minutes.
Transfer to a wire rack to cool.