Just checked with my mother and she said the traditional moon cake used to be sold at Thye Li, but now closed down liao....This year CNY, sister got it at a shop somewhere in Lorong Ah Soo... will find out and let you know. But, no guarantee the la pia quality is what you want...Cheers.
Thye Lee is located at Blk 108, Lorong Ah Soo and they are still in business.