A fragrant Pacific broth of tiger prawns simmered in coconut milk with lemongrass, chilli, and fish sauce.
New Caledonia's food culture is one of the most genuinely multicultural in the Pacific, shaped by the indigenous Kanak people alongside French colonists, Vietnamese indentured labourers who arrived from the 1890s onward, Indonesian and Wallisian communities, and later waves of immigration from metropolitan France. This coconut prawn soup is a dish that could only have emerged from that layering: the broth technique owes something to Vietnamese pho and Thai tom kha gai, the prawn is the star ingredient of the Kanak and French fishing traditions, and the fish sauce and lemongrass are fixtures of the Vietnamese-Caledonian kitchen that flourishes in Noumea's markets. The result is a soup with very few ingredients β six at its most stripped-back β that achieves an unusual depth of flavour through the careful sequencing of aromatics. The technique is uncomplicated but the timing is everything. Lemongrass is bruised and simmered in fish stock for a full five minutes before the coconut milk is added; this extracts the grass's volatile citronella and floral oils into the aqueous broth in a way that simply adding it with the coconut milk does not. When the coconut milk joins the broth it should be maintained at a gentle simmer β never a hard boil, which would cause the emulsion to break and the fat to separate into oily droplets. The prawns enter the pot last, cook for no more than four minutes, and are served immediately in warmed bowls. The test of a good version of this soup is the broth: it should be pale gold, lightly sweet, gently spicy, and balanced between the brackish depth of fish sauce and the brightness of lime added at the table.
Serves 4
Pour fish stock into a medium saucepan and add the bruised lemongrass stalks and sliced chilli. Bring to a simmer over medium heat and cook gently for 5 minutes, allowing the lemongrass oils to infuse the broth. The stock should turn faintly yellow and smell intensely citrusy.
To amplify the prawn flavour, simmer the reserved prawn shells in the stock for 10 minutes before adding the lemongrass, then strain them out. This is the step that separates a restaurant-quality result from a home version.
Reduce the heat to medium-low and stir in the coconut milk and fish sauce. Bring the soup back to a gentle simmer β you want lazy bubbles breaking the surface, not a rolling boil. Maintain this temperature while you taste and adjust: add more fish sauce for depth, a small pinch of sugar if the coconut milk is particularly sour, or an extra chilli if you want more heat.
Slide the peeled, deveined prawns into the simmering broth in a single layer. Cook for 3β4 minutes, turning once, until the prawns have curled into a loose C-shape and turned uniformly pink-orange throughout with no grey patches remaining at the thickest part.
If a prawn curls into a tight O-shape it is overcooked. Pull the pot off the heat the moment they hit that C-curve and serve immediately.
Remove the lemongrass stalks (they are too fibrous to eat). Squeeze the juice of one lime into the soup and stir. Taste the broth once more β it should be simultaneously rich, sharp, slightly spicy, and savoury. If any element is missing, this is your last chance to add a drop more fish sauce, lime, or a pinch of salt.
Ladle the soup into four warmed bowls, ensuring each receives a generous portion of prawns and broth. Scatter sliced spring onion over the surface and place a lime wedge on the side of each bowl. Serve immediately with jasmine rice or crusty bread for dipping.
Bruise lemongrass properly by pressing hard along its entire length with the flat of a large knife or a rolling pin β you should hear it crack. Without bruising, the flavour contribution is minimal.
Never let coconut milk boil hard. A vigorous boil breaks the emulsion and the soup becomes oily and grainy in texture. Medium-low heat with lazy bubbles is the target throughout.
Use full-fat coconut milk in a can, not carton coconut milk (which is watered down) and not 'light' coconut milk (which lacks the fat that gives the soup its velvety body).
Thia Tiparos or Megachef brand fish sauce is the professional standard for balanced, non-overpowering saltiness β generic supermarket fish sauce can be cloying or excessively salty. Taste before adding and adjust accordingly.
Serve within 5 minutes of cooking the prawns. Prawn texture deteriorates rapidly as they continue to cook in the hot broth even off the heat.
Add 100 g of thin rice noodles (soaked per packet instructions) to each bowl before ladling over the broth to transform this soup into a substantial one-bowl main course.
Crab version: replace tiger prawns with 400 g of fresh blue swimmer crab claws β simmer for 6 minutes and crack at the table for a more dramatic, Caledonian-feast presentation.
Mushroom and tofu version: replace prawns with 200 g each of oyster mushrooms and firm silken tofu cubed into 2 cm pieces; swap fish sauce for light soy sauce and use vegetable stock for a fully vegan soup with the same aromatic profile.
Richer laksa-style: stir 1 tablespoon of good-quality red curry paste into the aromatics before adding the coconut milk for a deeper, more Southeast Asian character that reflects the Vietnamese-Caledonian kitchen's influence.
Store the soup (without cooked prawns if possible) in a sealed container in the refrigerator for up to 2 days. Reheat the broth gently to just below a simmer, add fresh raw prawns, and cook them from raw for the best texture β reheated cooked prawns become rubbery. Do not freeze this soup as coconut milk separates on thawing.
New Caledonia's Vietnamese community, descendants of indentured workers brought to the nickel mines from 1891 to the 1940s, established a strong culinary footprint in Noumea and throughout the main island. Their tradition of aromatic broths, lemongrass cookery, and fish sauce seasoning merged with the Kanak reliance on seafood and the French love of refined stocks to produce soups like this one. Similar dishes appear throughout New Caledonian home cooking and are documented in contemporary Caledonian cookbooks as expressions of the territory's multicultural food heritage.
Yes β thaw them fully overnight in the refrigerator before using, and pat thoroughly dry before adding to the soup. Excess water from frozen prawns dilutes the broth and drops the temperature, extending the cooking time and increasing the risk of overcooking.
The broth has been boiled too hard, which breaks the coconut milk emulsion and causes the fat to separate. Unfortunately this cannot be fixed once it has happened. To prevent it, always keep the soup at a gentle simmer (lazy bubbles) rather than a rolling boil after adding the coconut milk.
Yes β the aromatic broth (stock, lemongrass, chilli, coconut milk, and fish sauce) can be made up to a day in advance and refrigerated. Reheat it very gently to just below a simmer, then add fresh prawns and cook immediately before serving. Do not add the prawns until you are ready to eat.
Lemongrass is difficult to truly substitute as its flavour is unique, but in a pinch you can use a combination of lime zest (from 1 lime), a small piece of fresh ginger, and a few kaffir lime leaves if available. The result will be different but still aromatic.
As written with one bird's eye chilli it has a moderate warmth β noticeable but not overwhelming. For a milder soup use a large red chilli (less heat per gram) or remove the seeds. For significant heat, add a second bird's eye chilli or a teaspoon of sambal oelek stirred into the finished broth.
Per serving Β· 4 servings total
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