Din Tai Fung is the sort of place you'd feel happy taking your mom for her first ever dumpling, or your gourmand friend for her thousandth. Particularly renowned for its soup dumplings, or xiaolongbao, this Taiwanese chain has branches all around the world—though surprisingly, only a few in Hong Kong.
The Causeway Bay branch is huge, clean, efficient, and Michelin-starred. The menu is overwhelming, ranging from drunken chicken to sesame and peanut noodles to beancurd topped with hairy-fisted crab roe; and including, of course, dozens of steamed dumplings, soup dumplings, wontons, and buns. There are even multiple different types of greens available.
If in doubt, go dumplings! (And perhaps a plate of greens to make you feel better.) The xiaolongbao really are wonderful, bursting with flavorsome soup. In contrast to some places, there's a discernible difference in taste between different types of filling—the crab roe and pork are particularly good.
You order by marking what you want on a piece of paper, so if you aren't sure what to expect, start with a few dishes and add on later. Prices are reasonable for what you get, and $50 or so should be enough to stuff two of you, including beer.