# Put the butter, which is softened at the room temperature, into a deep bowl.
# Add castor
sugar on it, mix it smoothly by your fingertips.
# Meanwhile, put the yolk aside and add the egg white and curd into the mixture.
# Finally, add the
flour by sifting while kneading the mixture. And knead it.
# Make the dough softy and smooth.
# After resting the dough for about 5-10 minutes, pick pieces from the dough which are a little bit smaller than
walnut. Roll the dough pieces between your palms, then shape them as small bars, which has about 2 inches length.
# Place the cookies onto the greased baking tray with some spaces between them.
# Spread the remaining yolk all over the cookies by a brush.
# Place the tray into the oven which is preheated to 356 F. Bake until the surfaces turn to red.
# After removing it from oven and cooling down, place them onto the service plates and serve them.