Ingredientsparts
- 4 large raw prawns (peeled and deveined)
- 1 small piece lemongrass (bruised)
- 10 g butter (or coconut oil)
- 200 ml full-fat coconut milk
- 1 stalk lemongrass (coarsely chopped and bruised)
- 2 cm fresh galangal (or ginger) (sliced)
- 1 tbsp fish sauce
- 1 tbsp brown sugar
- Juice of ½ lime
- handful of edamame beans (thawed)
- Chili oil (for the finishing touch)
Instructionsparts
Pat the cleaned prawns bone-dry. Place them in a vacuum bag with the bruised piece of lemongrass and the butter. Seal and store in the refrigerator.
Submerge the vacuum bag with prawns in a 60°C (140°F) water bath for 25-30 minutes.
Bring the coconut milk, lemongrass, galangal, fish sauce, and sugar to a gentle simmer. Let infuse on low heat for 20 minutes.
Strain through a fine-mesh sieve and set aside.
Pat the thawed beans bone-dry and toss with a drop of neutral oil.
Use a blowtorch to char the edamame beans until they show dark, roasted spots.
Bring the Tom Kha broth to a boil, remove from heat, and stir in the lime juice. Use an immersion blender to froth the soup into a thick, white emulsion.
Divide the prawns into black bowls. Pour the hot broth around them and spoon the white foam on top.
Garnish with the charred edamame and a drop of chili oil.
💡Tips & Notes
- •Sous-vide at 60°C keeps the prawns translucent and juicy; do not exceed this temperature or they will turn rubbery.
- •A chamber vacuum sealer is ideal for the prawns, but a zip-lock bag with the water displacement method works fine for this short cook.
- •Galangal has a sharper, more citrusy bite than ginger and is the authentic choice; only substitute ginger if galangal is unavailable.