Firstly, in a large bowl take 3 cup sona masuri rice and ½ tsp methi.
Then rinse well and soak in water until the rice is drowned for 4 hours.
Now, in another bowl take 1 cup urad dal and 2 tbsp toor dal.
Rinse well and soak in enough water for 2 hours.
Then, after soaking dal for 2 hours, drain off the water and transfer to the grinder. you can also grind in a mixer if you do not have access to a grinder.
Now, add water as required and blend to smooth paste.
The smooth and fluffy batter will be ready after 40 minutes.
Transfer the batter to a large vessel and keep aside.
Now, grind the soaked rice as well. Add the rice batter to the urad dal batter and mix well.
Ferment in a warm place for at least 20 hours or until the batter doubles in volume. If you are living in a cold climate, then you can place the batter in the warm oven (just heat the oven until it turns slightly warm and then turn off) to ferment.
Once the batter is well fermented, mix gently, without disturbing the air pockets.
Then transfer 4 cups of fermented batter to a small bowl and add 1 tsp salt.
Mix well until the salt is well combined. Dosa batter is ready. keep aside.