Take spice powder ingredients except for hing in a small pan.
Dry roast on medium heat with stirring continuously till dal is brown and you will get nice aroma from coriander seeds.
Let them cool completely. Grind them into a fine powder using a spice grinder.
Heat the oil in a pan on medium heat. Once hot add mustard seeds. Let them pop.
Then add chopped onions, green chilies, and curry leaves. Sprinkle some salt to speed up the process.
Cook till onion gets light brown.
Add pureed tomato and remaining salt. Cook till all the moisture from tomato evaporates and oil starts to leave from the sides.
Add prepared spice powder. Mix well and cook for a minute.
Add cooked rice. Mix gently till incorporated well.
Notes
Cook the rice beforehand and let it cool down completely before adding and mixing. If rice is hot then the grains will break and become mushy while stirring and mixing.
Instead of freshly ground spice powder, you can use readymade madras curry powder or bisi bele bath powder.
For instant pot method, see above the recipe card.