If you don't have cooked rice, cook rice and keep aside to cool.
Now take oil in a kadhai and heat it. Add mustard seeds, cumin seeds and gram dal and fry till they all sputter.
Now add the chopped onions and fry till translucent.
Add the ginger paste and slit chillies. Mix well and fry for about 3-4 minutes.
Now add the finely chopped tomatoes or puree.
Add turmeric powder, coriander powder, chilli powder, sambar powder and salt.
Cook well till the tomatoes are well cooked and the paste looks darker and releases oil.
Now turn off the gas and add the cooked rice.
Mix well so that all the rice is covered with the tomato paste.
Taste and adjust seasoning especially salt and heat.
Serve hot with raita or a boiled egg. Delicious to eat.