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.
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.
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!
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.