Heat half the oil in a large, nonstick wok and brown the pork over a high heat for 3–4 minutes. Remove from the wok and set aside.
Place the lemon grass, garlic, galangal or ginger, curry paste, turmeric and chillies in a food processor with the measured water and process until smooth.
Add the remaining oil to the wok and place over a high heat. Add the lemon grass paste and stir-fry for 2–3 minutes, then add the pork and stir-fry for a further 2–3 minutes.
Stir in the coconut milk and lime leaves, season and bring to the boil. Reduce the heat and simmer, uncovered, for 30 minutes, stirring occasionally.
Add the sugarsnap peas 6 minutes before the end of cooking and stir to mix well.
Remove from the heat and stir in the lime juice before serving with rice or noodles.