If preparing fresh cooked rice: Cook 1 cup of white rice with 2 cups of water in pressure cooker for 2 whistles in high flame.
Allow the pressure to release completely. Once cooled open the pressure cooker. Remove the rice and transfer it to a wide vessel so it cools off quickly.
Use the rice only when it is completely cooled off. So it is always better to prepare rice ahead 2 hrs, so it will have enough time to cool.
If using over night left over cold rice then skip off the above steps.
In a wide pan heat oil in medium flame. To this add mustard seeds.
As mustard seeds start cracking add chopped onions. Fry onions till they turn translucent.
Now add green chillies and curry leaves. Fry this for 1-2 mins.
Add chopped tomatoes. Cook till they are soft and mushy.
To this add turmeric powder, garam masala powder, salt and mix well. Cook this for 3-4 mins.
Now add cooled rice in batches to the prepared masala keeping the heat medium. Mix well.
Finally garnish with chopped coriander leaves and serve it with chilled raita.