Method

1. Peel and chop the onion, garlic and ginger.
2. Heat the oil in a large saucepan.
3. Add the chopped onion, garlic, ginger and cayenne pepper and fry gently for 10 minutes, taking care not to let the onion or garlic go brown.
4. Add the curry paste and stir well.
5. Add in the chopped sweet potato and mix well.
6. Add the passata and the stock. Bring to the boil, cover and simmer for 20 minutes until the potatoes are almost tender. 
7. Add the spinach and cook for a further 5 minutes.
8. Mix a few spoonfuls of the stew juices with the peanut butter to soften it and then mix it all back into the stew.
9. Season with black pepper and garnish with chopped coriander.