Din Tai Fung is not a Singaporean chain—it originated in Taipei—but it has flourished all over the city (and, in fact, the world—there is now a DTF in San Jose, CA) owing to the popularity of their delicious and addictive dumplings.
Making the perfect soup dumplings (xiao long bao) is a skill that takes years to perfect. You can see the experts hard at work in glassed-in kitchens at every DTF outlet. You'll find the ingredients on your table for the perfect dipping sauce accompaniment: soy sauce, black vinegar, and chili. Add a little of each to the shallow dish of thinly sliced ginger you're given and dip away.
I make at least monthly visits here for the crave-worthy xiao long bao and the ultimate comfort food: beef noodle soup. DTF's restorative, deep brown beef broth with thin noodles can be enjoyed with or without lashings of beef brisket. The spicy wontons in a vinegar sauce are also top-notch.