Ingredients
2 tbsp oil for frying
½ tsp mustard seeds
1 tsp cumin seeds
8-10 curry leaves
¼tsp asafoetida
2 long hot green chillies, cut into 2-3 pieces each
2 large onions, sliced finely
700g/1½lb potatoes, peeled and diced
½ tsp ground turmeric
½ tsp ground dried red chilli
1 tsp ground coriander
½ tsp ground cumin
225g/8oz tomatoes, chopped
1 tbsp fresh coriander, chopped
150g/5oz fine French beans, diced
salt

Method
1. Heat the oil in a medium sized, heavy-bottomed pan until it forms a haze.
2. Add the mustard seeds, cumin seeds, curry leaves, asafoetida and green chillies and cook until the mustard seeds stop crackling.
3. Add the onions and sauté until softened but not coloured, then add the potatoes. sauté until the potatoes are evenly coated in the oil and spices, then stir in the turmeric, chilli, ground coriander and cumin. Add some salt and enough water to half cover the potatoes.
4. Cover the pan with a tight fitting lid and simmer over low heat, stirring from time to time so the potatoes cook evenly. When the potatoes are almost done, add the tomatoes.
5. Cook uncovered until the potatoes are tender and the sauce has thickened. Add the beans, cook for a minute or two, season and mix in the chopped fresh coriander.