Finely chop the cheddar cheese and yellow cheese.
Cream the butter and sugar together.
Add the egg and mix well.
Sift cake flour, baking powder, and salt together and mix them in.
Add the chopped cheese to the dough and mix evenly.
Shape the dough into balls and place them on a baking tray.
Bake in a preheated oven at 180°C for 12-15 minutes.
Let cool to finish.