Pat the Catfish steaks dry and season them lightly with Fish sauce (nuoc mam) and freshly ground Black pepper; let rest 10–15 minutes so the flavors penetrate.
Heat a few tablespoons of Neutral oil in a heavy pot or clay pot over medium heat. Sprinkle in the Granulated sugar and cook, stirring occasionally, until it melts and turns a deep amber caramel.
Quickly add thinly sliced Shallots and minced Garlic to the caramel, stirring for 30–60 seconds until fragrant and slightly softened — be careful, it can sputter.
Carefully nestle the seasoned catfish into the pot, spooning the caramel and aromatics over the pieces. Sear the fish briefly, about 1–2 minutes per side, to coat with the caramel.
Pour in enough Coconut water to come about halfway up the fish, and add a little more Fish sauce (nuoc mam) to balance the sweetness. Toss in whole or sliced Bird's eye chilies according to how spicy you like it.
Bring to a gentle simmer, cover, and braise on low heat for 12–20 minutes until the fish is cooked through and tender, turning pieces once if your pot allows.
Remove the lid and increase the heat briefly to reduce the braising liquid until it becomes a thick, glossy glaze, spooning it over the fish so it is well coated.
Scatter chopped Scallions over the top and finish with an extra twist of Black pepper. Let the dish rest a minute off the heat so the sauce sets.
Serve the caramelized catfish hot, spooning the sticky sauce over steamed rice and enjoying the contrast of sweet, salty and spicy flavors.
