Steamed Fish Curry Custard (Hor Mok Pla)

Ingredients

Equipment Needed

• •Heavy granite mortar and pestle (krok), at least 8 inches diameter
• •Steamer (bamboo or stainless steel) large enough for 8 cups
• •Banana leaf cups or small ramekins
• •Clean kitchen towel for wrapping the steamer lid

Instructions

1. 1

   Pound the kreung tam

   Start with the dried chilies in the granite mortar. Pound them to a rough powder. Then the peppercorns. Then the salt from the kapi goes in to act as an abrasive. Add the lemongrass, galangal, and kaffir lime zest, pounding each addition until it breaks down before adding the next. Then cilantro root, garlic, shallots. Pound and scrape, pound and scrape. The paste should be smooth, fragrant, and deep red. When the aroma fills the room and there are no visible fibers left, you're done. This is the exact same paste you'd use for gaeng phet. Same ingredients, same technique. The difference is what you do with it next.

   Ajarn always said: the order matters in the krok. Hard and dry ingredients first, soft and wet last. Chilies and peppercorns break down first because they need the most force. Shallots go last because they're full of water and would splash everywhere if you started with them.
2. 2

   Build the custard base

   In a large bowl, combine the finished kreung tam with the thick coconut cream (reserve 4 tablespoons for topping). Beat the egg and add it in. Stir in the fish sauce, palm sugar, and shredded kaffir lime leaves. Mix until everything is completely incorporated. The mixture should be a uniform deep orange-red, smooth, and thick enough to coat the back of a spoon. Taste it. It should be salty from the nam pla, barely sweet from the palm sugar, rich from the coconut cream, and deeply aromatic from the paste. Adjust now, because you can't adjust once it's steaming.

   The egg-to-coconut ratio is what determines your custard texture. Too much egg and it's rubbery. Too little and it won't set. One large egg to 200ml of thick coconut cream gives you that silky, barely-set texture you're looking for. It should tremble when you nudge the cup. That's hor mok.
3. 3

   Line the banana leaf cups

   Place a few horapha (Thai sweet basil) leaves at the bottom of each banana leaf cup. The basil isn't just a garnish. It's a bed that perfumes the custard from below as it steams. If you can't find banana leaf cups, you can make them by cutting banana leaves into 6-inch circles, softening them over a flame for a few seconds so they become pliable, and pinning them into cup shapes with toothpicks. Or use small ramekins. The banana leaf is ideal, but the custard is the priority.

   Run banana leaves briefly over a gas flame or dip in hot water before folding. The heat makes the leaves flexible and releases that green, grassy fragrance that will infuse the custard. Stiff, cold leaves crack when you fold them.
4. 4

   Fill and layer the cups

   Lay a few thin slices of fish into each banana leaf cup on top of the basil. Pour or ladle the curry custard mixture over the fish, filling each cup about three-quarters full. Don't overfill. The custard will expand slightly as it sets, and you need room for the coconut cream topping. Tap each cup gently on the counter to settle the mixture and release any air bubbles.

5. 5

   Add the coconut cream cap

   Spoon about half a tablespoon of the reserved thick coconut cream onto the surface of each cup. It should float on top, forming a white layer over the red custard. This cap does two things: it insulates the custard surface during steaming, and it gives you that beautiful contrast of white cream over red curry when you serve. Top each with a few hair-thin strips of kaffir lime leaf and a ring or two of red chili.

6. 6

   Steam the custard

   Set up your steamer with water at a rolling boil. Place the cups in the steamer, cover with the lid wrapped in a clean towel to catch condensation (dripping water ruins the surface), and steam over medium-high heat for 15 to 20 minutes. The custard is done when it's set but still has a slight wobble in the center. Like a panna cotta. If you jiggle the cup and the surface doesn't move at all, you've overcooked it. It should tremble. Insert a toothpick: it should come out clean but moist. Pull them out and let them rest for 2 minutes. The residual heat will finish the set.

   The towel under the lid is not optional. Condensation dripping onto the custard surface creates pockmarks and dilutes the coconut cream cap. Every hor mok vendor in Thailand wraps the lid. Do the same.

Chef Tips

• •This is the same kreung tam as gaeng phet. Exactly the same. If you've already made red curry paste for another dish, use that. Hor mok proves that the kreung tam is a platform, not a recipe. One paste, multiple dishes. That's the system Ajarn always taught: understand the foundation, and everything else follows.
• •The fish must be firm and fresh. Snapper (pla krapong daeng) is the classic choice. Sea bass and barramundi work. Avoid soft fish like tilapia, which falls apart in the custard and gives you a grainy texture instead of clean, silky bites. Slice it thin so it cooks evenly within the custard.
• •Hor mok should never be dense or rubbery. If yours is, you used too much egg or steamed it too long. The texture you're looking for is like a very soft set custard: it trembles when nudged, holds a spoon mark, and melts on the tongue. The coconut cream provides richness. The egg provides structure. Respect the ratio.
• •The horapha (Thai sweet basil) lining the bottom is structural, not decorative. As the custard steams, the basil releases its anise-like essential oils upward through the entire custard. Skipping it is like skipping the kaffir lime leaf in a curry: technically the dish exists, but it's missing a dimension.
• •If banana leaves are unavailable, use small ceramic ramekins or even coffee cups. The custard will taste the same. You'll lose the grassy leaf fragrance, but the kreung tam and coconut cream carry the dish. Don't let the vessel stop you from making it.

Advance Preparation

• •The kreung tam can be pounded up to 2 days ahead and stored in an airtight container in the fridge. This is actually better: the flavors meld and deepen overnight. Bring to room temperature before mixing with the coconut cream and egg.
• •Banana leaf cups can be assembled a day ahead and stored stacked in the fridge, covered with a damp towel to keep them pliable.
• •The full custard mixture (paste, coconut cream, egg, fish sauce, sugar) can be combined up to 3 hours ahead and refrigerated. Add the fish to the cups just before steaming so it doesn't marinate and change texture.
• •Steamed hor mok is best eaten within an hour of cooking. It can be resteamed gently (5 minutes) if needed, but the texture is never quite as silky the second time.

Frequently Asked Questions

Nutrition Information

1 serving (about 225g)