Which kind of sugar?
For this recipe, we're using two types of sugar: rock sugar and brown sugar.
Rock sugar (Amazon) is a mild sugar that comes in a crystal chunk. It's widely used in Cantonese dessert soups like this, as well as braised dishes and sometimes to sweeten tea.
Another type of rock sugar that's common in Cantonese cooking is 片糖, slab sugar (Amazon), and if you have that instead, definitely use it for this soup! It's the same as rock sugar but with a stronger molasses flavor.
Brown sugar is probably much more familiar to you. The color comes from having molasses sprayed over white sugar, so there's just a bit more caramel-y depth to its sweetness compared to typical white granulated sugar.
If you don't have these sugars, or you can't have these, you can definitely use granulated sugar or other sweeteners!
Lotus seeds and lily bulbs in my soup?
These ingredients are both tasty and meaningful. Lotus seeds are associated with the newlywed blessing of having a child soon. Dried lily bulbs are associated with enjoying 100 years of happiness. Sounds great!
Their pale color also serves as a striking contrast in a bowl of red bean soup, and the ingredients add texture as well. If you can find them, definitely add them to this soup. If you can't, it's fine to omit them.