First, make the spicy sweet nam jim:
2 garlic cloves
3-4 red chillies (to taste)
2 fresh cilantro root
2 tablespoons palm sugar
3 tablespoons freshly squeezed lime juice
In a large pestle add the first three thing and roughly pound. Mash in the sugar, then add lime juice to taste.
Gut and descale fish. Perch works well as does snapper, and we've tried branzino and other bass but it's difficult if the fish is too big. Wash well and make some slashes in the skin with your knife. Then rub it all over with about 1/4 of the nam jim sauce you've made, getting it in the cavity and the slashes. Refrigerate the fish for a half hour.
Pat dry the fish, then dust with flour prior to frying... this will give the skin a crispiness. In a big wok, heat a couple inches of frying oil. Test the oil with a piece of potato... if the potato turns brown when you put it in, the oil is hot enough. Cook the fish for about 3 minutes per side until it looks like the photo.
Serve whole for a nice presentation. You can watch how to do this here: