In a mixing bowl, add urad dal, methi seeds, and moong dal. Rinse 3 to 4 times and add fresh water.
Cover and soak the grains for 5 to 6 hours.
Transfer to a blender jar, add water as required, and blend the soaked grains until smooth and bubbly.
Transfer the batter to a large bowl and add ragi flour, and water. Stir and mix the batter well until no lumps are seen.
Cover the bowl and allow the batter to ferment for 8 to 10 hours.
During the cold days, allow the batter to ferment in the preheated microwave for 8 - 10 hours (Preheat the microwave for 2 minutes).
After fermenting, the batter is almost doubled. Add salt and mix well.
Grease all the idli plates(oil or ghee) and pour the batter into the moulds.
Stack the plates and place them into the hot idli steamer and steam for 12 minutes on medium high heat.
Allow the idlis to cool down for 2-3 minutes. Using a spoon, scoop them out and serve hot with almond chutney or coconut chutney and sambar.