Put butter and sugar in a bowl and mix with a whisk.
Add the egg and mix well.
Sift flour and baking powder, add to the bowl, and fold with a spatula.
Add Jjorong (nuts or other desired toppings) and chocolate chips, and mix.
Shape the dough into round balls and place them on a pan.
Bake in the oven at 180°C for 12-15 minutes.