Step 1

Heat the oil in a saucepan. Add the mustard seeds and, when they sputter, add the curry leaves and green chillies.

Step 2

Saute for a few seconds and add the green tomatoes

Step 3

Add the coriander powder and turmeric and mix. Add a few tablespoons of water and when the water boils, put a lid on the saucepan and cook over medium-high heat about five minutes or until the tomatoes are soft. Green tomatoes are firmer and won't break down as much as ripe tomatoes would.

Step 4

Add half the coconut milk to the saucepan and bring to a boil. Add salt to taste and let the tomatoes cook another minute or two.

Step 5

Add the remaining coconut milk and salt, stir, and heat until the coconut milk is warmed through but not boiling.

Step 6

Turn off heat and serve.