1. Rinse the rice and urad dal separately and soak them in water for at least 4-6 hours.

2. After soaking, drain the water and grind the rice and urad dal separately in a blender or wet grinder until they become a smooth paste. You may need to add some water to achieve the desired consistency.

3. Mix the rice and urad dal paste together in a bowl, add salt to taste, and mix well.

4. Cover the bowl with a lid or plastic wrap and let the batter ferment overnight or for at least 8-10 hours. The batter should double in volume and become slightly sour.

5. After fermentation, mix the batter well and adjust the consistency by adding water if needed.

6. Heat a non-stick tawa or griddle on medium heat.

7. Grease the tawa with some oil using a tissue or brush.

8. Pour a ladleful of batter in the center of the tawa and spread it in a circular motion to form a thin crepe

9. Drizzle some oil on the sides of the dosa and cook until the edges turn golden brown.

10. Flip the dosa using a spatula and cook for another 1-2 minutes on the other side.

11. Serve hot with coconut chutney or sambar.