Preparation time: 1h 15 mins
Heat the oil in a large, deep pan, add the onion and fry gently for 5 minutes. Add the sweet potatoes and cook for a further 5 minutes, stirring occasionally.
Add the aubergine and courgettes, frying for 5 minutes more before adding the red pepper. Stir in the curry paste.
Add the tomatoes, soy sauce and stock and bring to a simmer. Cover the pan and cook for about 30 minutes or until the vegetables are tender.
Mix the cornflour with the yoghurt and stir into the pan. Simmer over a low heat, stirring frequently, until the sauce thickens. Cook for 2-3 minutes more, scatter over the chopped coriander and serve with pilau or plain boiled rice, Indian breads and chutneys.
Tip: Prepare the recipe the day before needed up to the end of step 3 then add the yoghurt and reheat to serve.
Variations: Ring the changes by adding other vegetables to the curry – try squash or pumpkin instead of sweet potato and cauliflower instead of the aubergine.