Cook the potatoes in a saucepan of lightly salted boiling water for 10 minutes. Drain and set aside.
Meanwhile, heat the oil in a large heavy-based saucepan, add the onion and fry gently for 5 minutes, stirring occasionally. Add the garlic and curry paste and cook for a further 2 minutes, stirring all the time.
Stir in the coconut cream, then add the tomatoes. Simmer uncovered for 2–3 minutes until the mixture resembles a fairly thick paste.
Add the carrots, cauliflower florets and stock, bring to the boil, then cover and simmer for 15 minutes. Add the beans and potatoes and cook for a further 8 minutes.
Stir in the prawns and simmer for 2–3 minutes, or until they turn pink. Season to taste, stir in the chopped coriander and serve straight away.