Dim Sum is actually an equivalent to the typical spanish tapas. These are small balls common in Cantonese cuisine that are usually served with tea since its origins. They are made by hand with dough, which can be made of flour, wheat or wheat starch, or Won Ton dough, and they are usually filled with pork, although there are versions in which they are filled with beef or even prawns. You have all the information in: «Dishes, desserts and other typical foods in Chinese gastronomy«.
You have all the information in: "Dishes, desserts and other typical foods in Chinese gastronomy".