1-Begin by peeling the 300g of whole prawns, placing the heads and shells into a pot while reserving the meat. Add 3 garlic cloves, 2 Thai chilies, 2 stalks of peeled lemongrass, 5 torn kaffir lime leaves, the 1.5 cm sliced galangal, 1/2 cup low sodium chicken stock, and 3 cups water. Bring this mixture to a simmer, cover, and cook for 10 minutes before straining the broth.

2-Return the strained broth to low heat and add 1/2 medium white onion cut into wedges and 120g oyster mushrooms, simmering for 3 minutes. Next, add 1 Roma tomato cut into wedges and simmer for 1 minute, then introduce the reserved prawns and cook for 2 minutes until they’re done.

3-Stir in 1 teaspoon sugar and 3 tablespoons fish sauce, simmering for 1 minute, followed by 3 tablespoons lime juice for the signature sour note. For the creamy version, incorporate 1 1/2 tablespoons Thai roasted chili sauce and 1/3 cup evaporated milk along with the sugar.