A 菜 (said A-cai, pronounced A-tsai) is a popular vegetable in Taiwan. Its name is derived from 萵仔菜 (pronounced e-á-chhài in Taiwanese/Min-nan dialect), which sounds like duck’s vegetable. According to my mom, it’s because ducks eat this vegetable.
You can find it in most Chinese supermarkets and it’s usually labelled as “A 菜”. It’s one of the things that my grandma knows in English; the other is Seven Eleven, which she calls “Seven” because it’s at almost every corner in Taiwan.
It’s easy to cook A-cai. You can stir fry with ginger or garlic, add salt to taste, and a bit of the mushroom seasoning. Cook with high heat and not for too long; it tastes “wilty” if you cook it too long. My mom also likes to add it to noodle soup.
A-cai has a distinctive flavour, not everyone likes it. I am not sure how to describe it and there isn’t anything that comes to mind to compare it to. It’s almost like romaine lettuce in shape and maybe a bit in taste.