This is a must have dish in our family mainly because we love dried oysters but also because it's one of those good fortune dishes that's essential to Chinese New Year although different families have different combos of good luck stuff. The Chinese name for dried oysters (ho see) sounds the same as "good things" and the hair algae (fat choy) sounds like the great wealth in "Gung Hey Fat Choy). So in this isolating New Year, if I make only one Chinese New Year dish, this is the one I'm making. We would usually have a casserole of this so that we have it for New Year's Eve but would also have it for the New Year.
For this dish, I also count some of my ingredients. I have 16 oysters, 8 (translates as "fat" or wealth) per casserole. I have 18 shitake mushrooms - 18 is a good number (wealth for sure!) but divide that by 2 is 9 - the number 9 has the same sound as the character (久) that means lasting a long time. I have a total of 8-9 ingredients for the dish and of course both are good numbers as one can gather by now...;-)
Other than the oysters and shitake, the other ingredients are not as easily counted so just go with what you have. "Fat choy" is very expensive and there are some fake stuff around. A cousin gave me a substantial supply more than 10 years ago and I am now down to a minimal supply that may last me a few more years if I only cook it once a year. You only need a 5 in. by 6 in. piece as it expands when soaked for a half hour in water. These are the three main ingredients. You can improvise the rest of the ingredients depending on what's available. I have used here the following (clockwise):
bamboo shoots (canned) - may need to be blanched in boiling water for 10 minutes to get rid of the smell typical of bamboo shoots
quail's eggs hardboiled and deshelled (18! they sell them fresh now in Chinese groceries but also available canned);
dried lily (soaked for a few hours) Fresh enoki mushrooms would be a better choice, but I forgot about it so used this to make up the 8 incredients but in the end added enoki when I remembered so ended up with 9 incredients, all good);
dried fish stomach (soaked for a few hours);
Dried cloud fungi 雲耳 (soaked for 1 hour)
Dried shitake (soaked for 5-6 hours)
Dried oysters (soaked for 3-4 hours); These are available frozen from Chinese herbal medicine stores. Try to get the medium sized ones that looked brown and not puffed up. They are usually not as good if they are too big and may not be as tasty. Price is around $30 CAD per lb in 2020. You get what you paid for.
Fat choy (available from Chinese herbal stores but watch out for fake, especially if too cheap)
Half a brick of red fermented soy bean curd 南乵泉 (optional)
Other possible substitutes include soy bean curd (my choice if it were available), deep fried tofu pockets (豆腐卜), or whatever you have around the house.
Heat up some oil in a pan, separately brown the hard-boiled quail's eggs, shitake, dried oysters, and bamboo shoots. Remove from pan, then heat up the fermented soy bean curd in the pan and toss the shitake, cloud fungi, fish stomach, dried lily, bamboo shoots into it. Add a cup of chicken stock, a cup of water and 3 teaspoons (or to taste) of premium soy sauce and simmer for about half an hour. At the end of the half hour, add the dried oysters and simmer for another 15 minutes. When done, add the Fat choy and quail's eggs and simmer for another 5 minutes, making sure there is at least a half cup or more of liquid left as the fat choy will soak it all up.
It is important to leave the fat choy in one clump and not break it up because it would disappear into the other ingredients if broken up. You can dig into it at dinner.
恭喜發財! (Gung hei fat choy!)