Indian recipe: Alu Mattar Rasa (potato and pea curry, Utter Pradesh style)

1 large onion
1 fresh red chilli
2 tsp chopped fresh ginger
2 tbs oil
1/2 tsp ground turmeric
2 tsp ground coriander
1 cup shelled peas
1 cup hot water
1 tsp salt
500 g potatoes, peeled and cubed
2 large ripe tomatoes, peeled and chopped
2 tbs yogurt
1tsp garam masala

Peel and roughly chop the onion. Seed the chilli and remove the stalk. Purée together the onion, chilli and ginger, adding a little water if necessary. Heat the oil in a heavy saucepan and fry the purée, stirring, for 3-4 minutes. Add turmeric and coriander and fry a little longer. Add the peas, hot water and salt, cover and cook for 10 minutes. Add the potatoes. If the peas are very young and tender, they can be added with the potatoes. When peas and potatoes are half-cooked, add the tomatoes and continue cooking for a few minutes more. Tahe the yogurt and stir with a little water until smooth, then add to the vegatables. Simmer until the cooking liquid thickens. Sprinkle with garam masala and stir gently to mix. Serve garnished with fresh cilantro (leaf coriander).