Suddenly I'm flushed with lots of rice paddy herb (ngo om, pronounced "n-gaw om") due to the nifty new growing tip I got recently. In the Vietnamese Kitchen, the classic use for this herb is in sour fish soup with tamarind, tomato, and okra. After reading the post on how to create makeshift greenhouses for the plants, several people asked what other uses there are for the citrusy-cuminy little darling.
My suggestion is to chop up the tender sprigs and use them to finish any kind of dish where you'd normally have cumin. In a curry that employs Madras curry powder and coconut milk, I found that a bit of rice paddy herb contributed a refreshing endnote. At a Viet restaurant in San Jose, I noticed that they added ngo om at the last minute to a braised dish featuring eel and turmeric.
Thinking out of the Viet box, I recently experimented with adding finely chopped ngo om to guacamole, a yogurt-based salad dressing, as well as a raita (Indian yogurt-based sauce). In these cases, the herb worked just fine. I just had this thought -- that rice paddy herb would probably be nice paired with legumes too, perhaps stirred into black beans right before serving or added to a vinaigrette to season cooked white beans or lentils, which would make a great summer salad or as a bed for panseared fish or scallop. A baba ghanoush-style roasted eggplant mash would get a nice lift from rice paddy herb.
So when you're cooking Vietnamese and non-Vietnamese food, think of rice paddy herb as a refreshing substitute for cumin (or enhancer of cumin's earthiness), a friend of turmeric, or just lovely on its own as a delicate seasoning. It's best chopped up since it's slender long stems are pretty to look at but awkward to chew. Whatever you do, DO NOT cook ngo om. Use it raw so you capture its essence well.
If you've got suggestions, share them with the rest of us!