Wash the ingredients 1-5 separately. Soak them in water, overnight.Drain out excess water from them. Grind the urad dal, fenugreek seeds and chana dal , having added water as required, to form a batter. Remove it into a bowl
Grind the white rice and ponni rice, having added water as required to form a batter. Pour it into the bowl.Add salt as per taste and mix thoroughly so that both the batter gets incorporated well.
Store it in a warm place and leave it to ferment.Once fermented, give the batter a gentle mix.
Heat the skillet. Drizzle few drops of oil and wipe it off with a paper towel.Pour a ladle full of batter in the middle of the skillet and spread the batter outward in a circular motion with a flat bottom steel bowl.
Once the dosa looks cooked and starts getting golden brown, drizzle few drops of oil over it. Remove it on to the serving plate
Serve hot with sambhar and coconut chutney.
My Tip: Chana dal brings about crispiness to the dosa and hence you shouldn't avoid using it.
You could avoid ponni rice, if its not available.
For the fermentation to happen during cold months, you could place it in the oven with its lights on/ preheat the oven slightly and turn it off and then place the bowl with the batter in it.