Pla Rad Prik (ปลาราดพริก)

The Sauce That Glazes

ปลาราดพริก means exactly what it does: pla (fish), rad (poured over), prik (chilli). The name hides the dish's real subject, which is the sauce. It is the Thai kitchen's most famous สามรส — the three flavours of sour, sweet and salty, backed by heat — built in the wok in minutes from garlic, coriander root and fresh chillies, then balanced with tamarind, fish sauce and palm sugar until it turns glossy and clings to the fish like a glaze.

The fish matters too, and every source treats it the same way: scale it, gut it, and บั้ง it — score the flesh with diagonal cuts on both sides — so it fries evenly and the sauce runs into the cuts instead of off the skin. A salt rub before it hits the oil keeps the skin from sticking and seasons as it cooks.

The dish spans the whole of Thai cooking, which is why the recipes disagree so cheerfully. The from-scratch school pounds fresh garlic, coriander root and chillies (Wongnai's home cook, TrueID's version of the same, and Pim's kitchen). The shortcut school starts from a bottle of sweet chilli dipping sauce and adjusts it with vinegar and fish sauce — Wongnai's editorial recipe says so outright, and Sanook's version was written for a weeknight. And Kapook's curry-paste pot swaps the fresh chilli for red curry paste entirely, making ปลาราดพริกแกง: same fish, same pour, different heat.

The Recipe (from-scratch three-flavour sauce, from Wongnai / TrueID / ครัวบ้านพิม)

The shortcut pot (Wongnai editorial): one cup of ready-made sweet chilli dipping sauce replaces the whole seasoning — fried with Thai garlic, coriander root and five red chillies, loosened with tamarind and water. The restaurant pot (ครัวบ้านพิม): 200 g palm sugar plus 50 g white sugar, half a cup of thick tamarind, a quarter cup of pickled garlic brine and a third of a cup of pickled garlic cloves — the brine doing the souring alongside the tamarind. The curry pot (Kapook): red curry paste pounded from dried chillies, shallots, garlic, galangal, lemongrass, kaffir lime zest and shrimp paste, fried and poured over the same crisp fish.

The Method

1. The fish. Scale, gut and wash the fish, then score it with three or four diagonal cuts on each side — Pim insists on a sharp knife so the cuts are even and the fish fries flat. Rub with salt, inside and out, and pat dry with kitchen paper; TrueID is explicit that a wet fish spits and steams instead of crisping.
2. The fry. Heat the oil well — TrueID fries over a very hot flame for four to six minutes on the first side, then less on the second — until the fish is golden and the scored edges crisp up. Lift out and drain. Wongnai's home cook dusts the fish with a little crispy-frying flour first if she wants the skin to shatter.
3. The paste. Pound or chop the garlic, coriander roots and red chillies together. The coriander root is not negotiable — it is the three-flavour sauce's signature note, and Wongnai's editorial recipe names it as part of the Thai kitchen's สามเกลอ, the trio of garlic, coriander root and pepper.
4. The sauce. Fry the paste in a tablespoon of oil over a low-medium flame until it smells sweet and garlicky, then add the tamarind water, fish sauce, palm sugar and water. Cook for four to five minutes, stirring, until the sugar has dissolved and the sauce is glossy — it should coat a spoon, not run off it. If it will not thicken, simmer a little longer; the sugar is the thickener.
5. The balance, then the pour. Taste and adjust all four corners — sour, salty, sweet, hot — until no single one leads. Pour the sauce over the fish so it pools in the score marks, scatter coriander and sliced red spur chilli over the top, and serve at once with hot jasmine rice while the skin is still crisp.

Where Thai Sources Disagree

How Western Versions Get It Wrong

• Sweet chilli sauce from a bottle, served cold. Even the Thai shortcut school fries bottled sauce with garlic and chilli and adjusts it. Squeezing cold sauce over hot fish is what Thai cooks would call a fridge dish, not a cooked one.
• Skipping the scoring. The diagonal cuts are not decoration — they cook the thickest part of the fish and hold the sauce. An unscored fish fries unevenly and the sauce slides straight off.
• A watery, cornflour-thickened sauce. Three-flavour sauce thickens from dissolved sugar reduced in the wok; it should glaze, not gum. Sanook's cornflour slurry is the shortcut school's emergency brake, not the standard.
• Leaving out the coriander root. Western recipes swap coriander leaf for coriander root and the sauce loses its backbone. The root is the one ingredient every from-scratch Thai source insists on.
• Frying a wet, unscored fish. Pat it dry, salt it, score it — otherwise the skin sticks, the oil spits and the fish steams instead of crisping.

UK Ingredient Notes

• Fish: whole sea bass or bream from any UK supermarket counter or fishmonger; tilapia (ปลานิล) is sold frozen at Asian grocers. Ask for the fish scaled and gutted, and score it at home.
• Coriander root (รากผักชี): buy coriander in bunches with the roots still attached — Thai and Vietnamese grocers sell it this way. If you can only find trimmed coriander, use the thickest part of the stems instead.
• Red bird's eye chillies (พริกจินดาแดง): Thai grocers stock them; supermarket bird's eye chillies (red or green) are hotter, so use two or three instead of five.
• Tamarind water (น้ำมะขามเปียก): a block of tamarind pulp soaked in warm water and squeezed, or tamarind concentrate from any Asian grocer. Avoid the sweetened Indian-style chutney.
• Palm sugar (น้ำตาลปี๊บ): soft light brown sugar is a workable stand-in; the sauce's gloss comes from the sugar, so do not use sweetener.
• Pickled garlic (กระเทียมดอง): jars at Thai and Chinese grocers — Pim's restaurant trick needs both the cloves and a splash of the brine.

Sources

This recipe is translated from the following Thai-language sources. Where they disagree, we've said so.