Peel the shallots. I find that small purple shallots (like Phan Rang shallots) give the best flavor, but if they’re small, use 5-6. Blend the shallots and red chili pepper together in a food processor until finely chopped.

Remove the skin from the pork and cut into small cubes, including both fat and lean meat. Pork shoulder fat is best because it stays tender and absorbs flavor without becoming greasy after cooking.

Cut the fish into thick slices about 1 1/4 inches (3 cm) wide. Don’t cut too thin or the pieces may fall apart. Marinate the fish with 1 teaspoon black pepper, all the fish sauce, 1/3 of the blended shallot-chili mixture, a little cooking oil, and toss to coat. Let it sit for about 15 minutes while you prep the other ingredients.

Heat an enameled clay pot over medium heat. Add the pork fat and cook until the lean pieces turn light golden. Add the palm sugar and stir until it caramelizes. Add the remaining shallot and chili mixture and sauté until fragrant. Remove the pot from the heat, arrange the fish pieces in the pot, then return to the stove. Rinse the marinade bowl with a little water and pour it into the pot. Add more water if needed so the liquid just covers the fish. Add the bird’s eye chilies.

Bring the pot to a boil, skim off any foam if needed (though I rarely see any), then reduce to medium-low and simmer gently. Taste and adjust seasoning if needed—the sauce should taste a little under-seasoned at this stage, as it will concentrate as it reduces. When the sauce thickens and becomes glossy, sprinkle the remaining black pepper over the fish. Simmer a bit longer. If you like, add some chopped green onion at this point.

That’s it! Serve hot with steamed rice, or dip crispy rice in the sauce—it’s delicious.