Cream salted egg yolks, butter, sugar, condensed milk and milk powder together to form a paste. Set aside.
Combine dough ingredients to form a smooth dough. Leave to rest for 1–2 hours until risen. Roll dough out on a floured surface into a long cylinder. Divide into 18 equal pieces.
Roll each dough piece out into a thin, round skin. Spoon some salted egg mixture onto each skin. Bring edge of skin up to enclose filling. Pinch edges to seal buns. Place buns in patty tins, pinched side down.