Coat lamb in 2 tsp olive oil. Heat remaining oil in the medium saucepan. Add onion and cook over low heat until soft. Remove from heat and add sweet potato.
Heat a large frypan and brown lamb in 200g batches, transferring to the saucepan with the onion and sweet potato when browned. Add curry paste to frypan and cook for 1 minute before adding water. Stir to combine and pour into the saucepan.
Bring the saucepan to the boil. Reduce heat and simmer covered for 45 mins. Add coconut milk, zucchini and peas and simmer for 5 mins or until tender. Serve with roti, rice, natural yoghurt and mango chutney.
