Sauté shallots, garlic, ginger and halved lemongrass stalks, do not brown! Pour in the stock and coconut milk, simmer for about 15 minutes. Add the peas, simmer for another 10 minutes. Remove lemongrass, puree the rest and strain through a sieve. Season with salt, pepper and chilli flakes.
This goes well with shrimp skewers, smoked salmon strips or fresh cubes of salmon fried or poached, or small plaice rolls on a lemongrass stalk.