Toast coriander and cumin seeds in a dry pan until fragrant.
Pound seeds with shallot, chillies, garlic, ginger, lemongrass, and salt into a paste.
Grind coriander stalks and kaffir lime leaves into the paste until smooth.
Season the paste with fish sauce and white pepper.
Fry aubergine in vegetable oil for 15 minutes until golden-brown and soft.
Fry green curry paste with the solid coconut fat for 3 minutes.
Stir in remaining coconut milk and green beans then simmer for 3 minutes.
Thicken the sauce slightly then add the chicken stock.
Stir in the sugar and fish sauce.
Cook prawns in the sauce for 5 minutes until pink.
Add lime juice, zest, chopped coriander, and kaffir lime leaf.
Serve over jasmine rice garnished with coriander leaves.