*** please note that the measurements are just approximations. ***
Chop tomatoes to small pieces and cook them in about 250ml of water and turmeric powder.
Grind coconut, mustard seeds, red chillies with 2 to 3 tblsp of yogurt and a little water, to a fine paste. make sure that the paste is not very watery.
Once the tomotoes are cooked, add the ground paste, remaining yogurt, salt to taste and the sugar. You may add some water to the mixture if the consistency is thick.
When the mixture starts to boil, remove from heat.
Season with mustard seeds and curry leaves.
Serve with rice.
** you may use fresh cucumber instead of tomatoes. in that case do not cook cucumber in water and turmeric powder. make a fine paste of coconut, green chillies, mustard seeds - mix with yogurt - add the cucumber and salt. this tastes fantastic with hot puris. **