If you don't balance those spices you'll be serving Tom Yuck
Hot, sour, salty and fragrant all at once, tom yum is a balancing act on a spoon. Make your own roasted chilli paste, build a stock from prawn shells and taste, taste, taste. The prawns get about 90 seconds of fame, so don't wander off.
The challenge
- Sourcing fresh aromatics
- Balancing sour-spicy-salty
- Grinding paste consistency
- Preventing curdled coconut milk
- Seafood cooking time
Thai hot and sour soup that demands a homemade chili paste and perfect balance of flavors. You're pounding aromatics into a fragrant paste using a mortar and pestle. The broth walks a tightrope between sour lime juice, salty fish sauce, and fiery chili heat, and getting that balance right takes tasting and adjusting throughout.
If using coconut milk, it can't boil or it separates into an oily mess. Prawns or other seafood go in at the very end and overcook in seconds, turning rubbery if you're not paying attention.
Prep: 45 minutes ย ยทย Cook: 45 minutes
Ingredients
For the roasted chilli paste
- 6 large dried red chillies, seeds removed, soaked in hot water for 15 minutes
- 4 Asian shallots and 4 garlic cloves, peeled and sliced
- 1 tbsp dried shrimp, soaked for 10 minutes
- 1 tbsp palm sugar and 1 tbsp tamarind paste
- 60 ml (1/4 cup) neutral oil
For the soup
- 600 g (1.3 lb) large raw prawns (shrimp), shell and head on
- 1.2 litres (5 cups) water
- 3 stalks lemongrass, trimmed, bruised and cut into 5 cm (2 in) lengths
- 5 cm (2 in) piece galangal, thinly sliced
- 6 makrut lime leaves, torn, centre vein removed
- 200 g (7 oz) oyster or straw mushrooms, torn or halved
- 4-6 bird's eye chillies, lightly bruised
- 3-4 tbsp fish sauce
- 4-5 tbsp fresh lime juice (about 3 limes)
- 200 ml (3/4 cup) coconut milk or evaporated milk (optional, for a creamy version)
- A handful of coriander (cilantro) leaves
Method
- Shop for fresh aromaticsLook for firm, fragrant lemongrass, pinkish-white galangal and glossy makrut lime leaves at an Asian grocer. Fresh makes a huge difference; frozen galangal and lime leaves are a good backup, dried are a last resort. Ginger is not a substitute for galangal.
- Make a prawn stockPeel and devein the prawns, keeping the heads and shells. Chill the prawn meat. Heat 1 tbsp oil in a pot over medium-high heat and fry the heads and shells for 3-4 minutes, pressing on the heads, until bright orange and fragrant. Add the water, bring to a boil, then simmer for 20 minutes. Strain, pressing hard on the shells. You should have about 1 litre (4 cups).
- Fry the paste ingredientsWhile the stock simmers, drain and pat dry the chillies and dried shrimp. Heat the 60 ml oil in a small pan over medium heat and fry the shallots and garlic for 4-5 minutes until golden. Add the chillies for 1 minute until they darken slightly (don't burn them). Lift everything out with a slotted spoon, keeping the oil.
- Pound it smoothIn a mortar, pound the fried chillies, shallots, garlic and dried shrimp to a fine paste, about 5-8 minutes. Work in a circular grinding motion as well as pounding. Return to the pan with the palm sugar, tamarind and 2 tbsp of the reserved oil and cook over low heat for 3-4 minutes until thick, dark and jammy.
- Infuse the brothBring the strained stock back to a simmer. Add the lemongrass, galangal and lime leaves and simmer for 5 minutes to release their perfume.
- Add mushrooms and pasteAdd the mushrooms and 2 tbsp of the chilli paste and simmer for 2 minutes. Add 3 tbsp fish sauce.
- Go creamy (optional)If using coconut or evaporated milk, turn the heat right down so the soup is barely shimmering, around 85ยฐC (185ยฐF), and stir it in. From here it must not boil or it will split.
- Cook the prawnsAdd the prawns to the gently steaming soup and cook for 60-90 seconds, just until they turn pink and curl into a loose 'C'. A tight 'O' means overcooked. Take the pot off the heat immediately.
- Balance off the heatAdd the bruised bird's eye chillies and 4 tbsp lime juice off the heat (boiling lime juice makes it bitter). Taste and adjust: more lime for sour, more fish sauce for salt, more paste for heat and depth. It should be boldly sour first, then salty, then hot.
- ServeLadle into bowls, making sure everyone gets prawns and mushrooms, and scatter with coriander. The lemongrass, galangal and lime leaves are for flavour, not eating, so push them aside.
- Sweat-check your guestsWatch faces closely after the first sip. One tear means perfect balance. Two tears means pass the rice. No tears at all means you've made Tom Mild. Give yourself a high five either way.
Tips from the trenches
- Prawn heads are flavour gold. Don't skip the shell stock, it's what makes a restaurant-level tom yum.
- Leftover chilli paste keeps for weeks in a jar in the fridge and is brilliant in stir-fries.
- Balance in small steps: half a teaspoon of fish sauce or lime at a time, tasting between each addition.
- No mortar and pestle? A small blender works for the paste, but add a splash of the oil to help it move.
โFood is celebratory. People who don't cook don't know how much fun they're missing.โโ Leo Buscaglia
