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Cá thu kho trà xanh / Braised fish with green tea

Growing up, my family cooked cá kho/braised fish the Northern way and it was never a favorite dish until much later. Northern style cá kho is ascetically simple and intense.  Southern style cá kho is easier to like – the fish is more softly presented and embellished with a more prominent sweetness. When we experimented with adding tea (a typically Northern touch) to Southern style cá kho, we found that the flavors of braised fish and the fragrance of tea were well matched companions still. Using Japanese or Korean barley tea made for an even more intriguing dish with a novel taste while the tea leaves themselves can be roasted to form a crust on the fish filet, adding a new textural element.

Cá Thu Kho Trà Xanh

To make cá thu kho trà xanh, a good fishy fish with high oil content is essential. Dryer fish would not put up a good fight against the stringency of green tea; oily fishy fish on the other might be a bit much by themselves but are very well behaved braised with tea. We love using mackerels or blue fish for this dish.

The original cá kho recipe is absurdly easy. Like other recipes courtesy of Oanh’s mom – we have the full ingredients listing here:

  • Fish – 2 filets (or 1 mackerel)
  • Nước mắm / fish sauce – 3 tablespoons
  • Sugar – 1 teaspoon
  • Black pepper – a pinch
  • Onions – a few slices / 1 chopped up shallot
  • Oil – ½ teaspoon
  • Coconut soda – 1 can
  • Green tea – 1 tablespoon

We used oolong (partially oxidized green tea) or genmaicha (green tea with roasted barley.) The effects of the oolong were subtler, while the roasted barley helped push genmaicha to foreground. I preferred the former while Oanh preferred the latter.

A pot of tea, in a way


We put in oil and onions and half of the dry tea into a small cooking pot – that can accomodate our filets in one layer. The fish filets went in next, then the rest of the tea, black pepper, sugar, and fish sauce. We poured in enough coconut soda to cover the filets and simmered for half an hour or until the broth is almost gone. That’s it!

One layer of fish

When we wanted to be fancy, we fished the filets out and placed them on a baking pan. Then we covered them with the cooked tea leaves. A quick broil in the oven dried out the tea and leave a crunchy sweet caramelized crust on the filets.


Incidentally the slightly crunchy caramelized crust was always my favorite part of Northern style cá kho. Southern style filets were too moist (not a bad thing) to achieve that outer crust. But with this combination, we had the best of both styles.


  1. Once again I think I’ll agree with Oanh: I’d prefer fish with genmaicha (or any kind of Japanese green tea) :D, not only because of the roasted rice but also the umami note of the leaves themselves.

    And welcome back! You guys have been so quiet on the blogging front! Too busy rolling in the dough from the tofu business? 😉

    • Oanh says ‘Yay! Thanks for agreeing with me, Mai :)’ – the two of you are getting to be a regular agree-team, I say.
      Homer and Skinner

      I know, I know, we’ve been deliquent about blogging. Wish there were more time in the day. Too busy for sure but not quite rolling in anything yet. Only metaphors could describe how hard Oanh has to work and they all sound gross when taken literally in a foodmaking context.

  2. I’ll keep this recipe in mind the next time I make cá kho. When you wrote that adding tea is a “typically Northern touch”, were you referring to cá kho recipe(s) only or recipes in general? My grandma came from the north and she loved tea 🙂

    • Hi Ngan, I was referring to cá kho recipes. Cá thu kho trà is something that my grandmother makes, my mom too.

  3. I sometimes use trout or salmon. Mackerel is lovely, too. My mom uses cá chim sometimes. Happy kho-ing guys.