Soak rice and urad dal separately in water overnight. Grind them separately.
Mix and make soft batter. Keep it covered for 8 hours. Add fenugreek seeds paste.
Heat a griddle. Sprinkle water. Keep the heat medium low. Pour 1-tsp. full of the batter and quickly spread into a thin pancake. Add oil. Fry on both the sides.
Make this dosa as thin as possible. Serve them in triangle or round shape.
Serve with chutney and sambhar.