Gāngyāgǒu has been making Ningbo's signature dumplings (宁波汤圆, Ningbo tāngyuán; six for ¥16), silky boiled rice cakes stuffed with sugar-spiked ground sesame, since 1926. They also come in more inventive flavours, such as rose (玫瑰, méiguī) and pumpkin (南瓜, nánguā). You can make a meal out of it by ordering some xiǎolóngbāo (小笼包, soup dumplings; ¥19 to ¥36). There's a picture menu.
There is ample seating in the split-level restaurant, which you can find at the southeast of the Tianyi Plaza; look for a bronze sculpture of a dog, duck and dumplings.