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Tho Ruang Hor Mok: Steamed Thai Fish Custard

The first time I tasted hor mok, I was utterly captivated. It wasn’t at a fancy restaurant, but rather from a tiny, bustling stall tucked away in a Bangkok side street, perfumed with the heady aromas of lemongrass and chilies. A kind woman with a radiant smile served it to me in a small banana leaf cup. The silken texture, the vibrant spices, and the delicate dance of sweet and savory – it was an experience that transported me, and one I’ve chased ever since. Recreating that perfect bite in my own kitchen has been a delicious journey, one I’m excited to share with you.

Recipe Overview

Prep Time: 25 minutes
Cook Time: 18 minutes
Total Time: 43 minutes
Servings: 6
Yield: 6 ramekins
Dietary Type: Dairy-Free

Ingredients

1 1/2 lbs grouper (boneless and skinless) or 1 1/2 lbs red snapper fillets, finely chopped (boneless and skinless)
2 cups coconut milk
1/3 cup red curry paste
1 tablespoon fish sauce
2 1/2 teaspoons palm sugar, finely chopped or 2 1/2 teaspoons packed dark brown sugar
2 eggs
13 kaffir lime leaves, very thinly shredded
Kosher salt, to taste
1/4 cup basil leaves, chiffonade cut
1 1/2 teaspoons cornstarch
1 red Thai chile, stemmed and very thinly sliced crosswise

Equipment Needed

Food processor
Measuring cups and spoons
Ramekins (6)
9″ x 13″ baking pan
Saucepan (1-qt)

Instructions

Preheat your oven to 350 degrees F (175 degrees C). Preparing the oven early ensures consistent cooking temperature for the custard.
In a food processor, combine the fish, 1 cup of the coconut milk, the red curry paste, fish sauce, 2 teaspoons of the palm sugar (or brown sugar), and the eggs. Process until the mixture is very smooth, about 1-2 minutes. The mixture should be almost like a thick batter. Ensure there are no lumps of fish remaining.
Remove the mixture from the food processor and transfer to a mixing bowl. Stir in 12 of the finely shredded kaffir lime leaves. Season with kosher salt to taste. Be mindful that the fish sauce already contributes saltiness.
Gently fold in the chiffonade-cut basil leaves into the fish custard mixture. This will add a fresh, aromatic element to the custard.
Divide half of the fish custard evenly between the ramekins.
Top each ramekin with the basil leaves.
Spoon the remaining fish custard on top of the basil leaves in the ramekins.
Place the ramekins in the 9″ x 13″ baking pan. This will create a water bath, which gently cooks the custard.
Carefully pour boiling water into the baking pan so that it comes halfway up the sides of the ramekins. The water bath ensures even cooking and prevents the custard from drying out.
Bake in the preheated oven until the custards are set and begin to pull away slightly from the sides of the ramekins, about 16 minutes. Keep a close eye on the custards. Overbaking can result in a rubbery texture.
While the custards are baking, prepare the coconut milk topping. In a 1-quart saucepan, combine the remaining 1 cup of coconut milk and remaining 1/2 teaspoon of palm sugar (or brown sugar) with the cornstarch.
Place the saucepan over medium-high heat. Cook, stirring constantly, until the mixture thickens, about 2 minutes. The cornstarch will act as a thickening agent, creating a creamy sauce.
Once the custards are done, remove the baking pan from the oven. Carefully remove the ramekins from the water bath.
Top each ramekin with some of the thickened coconut milk sauce.
Sprinkle each custard with the remaining shredded kaffir lime leaf and the very thinly sliced red Thai chile. These garnishes add both visual appeal and bursts of flavor.

Expert Tips & Tricks

Fish Selection: While the recipe calls for grouper or red snapper, other firm white fish like cod or halibut can be used. Just make sure the fish is fresh and of high quality.
Curry Paste Quality: The quality of the red curry paste will significantly impact the flavor of the dish. Opt for a high-quality, authentic paste for the best results. Consider making your own for ultimate control over the ingredients and spiciness.
Water Bath Temperature: Using boiling water for the water bath is crucial. It helps to jumpstart the cooking process and ensure even heat distribution.
Checking for Doneness: The custards are done when they are set around the edges but still have a slight jiggle in the center. They will continue to set as they cool.
Spice Level: Adjust the amount of red curry paste and chile to suit your spice preference. Start with less and add more to taste.
Make-Ahead Tip: The fish custard mixture can be prepared a day in advance and stored in the refrigerator. This allows the flavors to meld together. Add the basil just before baking.
Alternative Baking Method: If you don’t have ramekins, you can steam the custard in individual banana leaf cups for a more traditional presentation. Adjust the cooking time accordingly.

Serving & Storage Suggestions

Serve the tho ruang hor mok warm, straight from the ramekins. The contrasting flavors and textures make it a delightful experience. The vibrant colors also make it a beautiful dish to present.

Leftovers should be stored in the refrigerator in an airtight container. They will keep for up to 2 days. Reheat gently in a steamer or microwave. Be careful not to overheat, as the custard can become rubbery.

I do not recommend freezing the custard, as the texture will change significantly upon thawing.

Nutritional Information

Nutrient	Amount per Serving	% Daily Value
Calories	362.9 kcal	N/A
Calories from Fat	129 g	36%
Total Fat	14.4 g	22%
Saturated Fat	12.1 g	60%
Cholesterol	88.2 mg	29%
Sodium	279.1 mg	11%
Total Carbohydrate	40.1 g	13%
Dietary Fiber	0.2 g	0%
Sugars	38.3 g	153%
Protein	18.4 g	36%

Variations & Substitutions

Vegan Option: Substitute the fish with finely chopped firm tofu. Use a vegan red curry paste and replace the fish sauce with soy sauce or tamari. Replace the eggs with a flax egg (1 tablespoon ground flaxseed mixed with 3 tablespoons of water, let sit for 5 minutes).
Seafood Medley: Incorporate other seafood, such as shrimp or scallops, along with the fish. Adjust the cooking time accordingly.
Spice It Up: For a spicier version, add more red curry paste or use a hotter variety of Thai chile.
Vegetable Addition: Add finely chopped vegetables like bok choy or Chinese broccoli to the custard mixture.
Herb Infusion: Experiment with different herbs like cilantro or mint in addition to or instead of the basil.

FAQs (Frequently Asked Questions)

Q: Can I use frozen fish for this recipe?
A: Yes, you can use frozen fish, but make sure it is completely thawed and patted dry before using it. Excess moisture can affect the texture of the custard.

Q: What if I don’t have kaffir lime leaves?
A: Kaffir lime leaves are essential for the distinct flavor of this dish. If you can’t find them, you can substitute with lime zest and a small amount of lime juice, but the flavor will not be the same.

Q: How do I prevent the custard from becoming rubbery?
A: Avoid overbaking the custard. It should be set around the edges but still slightly jiggly in the center. The water bath also helps to prevent it from drying out.

Q: Can I make this recipe without a food processor?
A: While a food processor is recommended for achieving a smooth texture, you can finely mince the fish and thoroughly mix it with the other ingredients by hand. Be prepared for a slightly different texture.

Q: What is the best way to reheat leftover hor mok?
A: The best way to reheat leftover hor mok is by gently steaming it. You can also use a microwave, but be sure to use low power and check it frequently to avoid overheating.

Final Thoughts

I urge you to embark on this culinary adventure and recreate the magic of Thai street food in your own kitchen. Don’t be intimidated by the ingredients or the steps; each component contributes to a symphony of flavors and textures that is truly unforgettable. The tho ruang hor mok is not just a dish; it’s an experience, a journey to the vibrant streets of Bangkok with every bite. I hope this recipe brings a little bit of that magic into your life. Share your creations with me and let me know what you think! Perhaps pair it with a refreshing Thai iced tea for the ultimate dining experience.

Tho Ruung Hor Mok (Steamed Thai Fish Custard) Recipe