Tong Heng Confectionery     Tong Heng Confectionery has wriggled its way to the top of the Egg Tart food chain scene in Singapore and almost any egg-tart lover would have at least heard of this confectionery shop. Situated in the heart of China Town, Tong Heng and the diamond egg tarts ($1.60) they sell have become one of my most frequented stores. The egg tarts have a slighly flaky but still hard texture with an almost jelly-like, candied egg-custard filling. Simply del