The food served at Taiwanese night markets can be fad-driven, but this Taiwanese delicacy has stood the test of time. When thinking of Taiwanese street food this must be one of the first dishes that springs to mind. It’s called O-a-chian (蚵仔煎) in Taiwanese. Don’t bother learning its Mandarin name, no one will understand. In English, you could call it Taiwanese Oyster Omelette.
Oyster omelette is popular throughout southern China and the parts of south-east Asia where Chinese immigration has been strong. There are lots of regional variations in the omelette, even within Taiwan there is locational variety. Kinmen’s O-a-chian is different from what you might find at a night market in Taipei or Tainan.
The standard Taiwanese Oyster Omelette is made primarily of eggs, small oysters, some 小白菜 (I’m unsure of the English, it’s something from the Chinese cabbage/bok choy family), and sweet potato starch. The starch is combined with water and mixed with the egg, giving the egg layer a thick snot-like consistency. Then the omelette is covered in a slightly sweet sauce. I’ve never seen this sauce outside Taiwan. To help you understand its flavor, I found some recipes for making a substitute if you don’t live in Taiwan. One example calls for heating ketchup, vinegar, miso paste, soy sauce, and sugar together with cornstarch and water. I imagine that would taste approximately correct.
O-a-chian tastes good. It has a nice savory flavor, but what it’s really about is its texture. Chinese cooking is unusually concerned about textures and mouth-feel. Many things that seem inedible to outsiders are part of Chinese cuisine because of mouth-feel; tendons, chicken gristle, shark’s fin, bird’s nest, sea cucumber, etc. O-a-chian combines the chewiness of sweet potato starch with the delectable tenderness of the oysters. There’s the crispness of the lightly fried green leafy shit, along with the feel of golden fried eggs. It’s good taste and good feel combined.
If you visit Taiwan this is a classic Taiwanese street food that you really need to try. In Taipei, look for it in and around night markets. O-a-chian is more common outside Taipei, where you should be able to find it in neighborhood restaurants, as well as the night market.