3 cups white long grain rice
1 1/4 cup urad or white gram lentils
1/4 tsp fenugreek (optional)
Salt to taste
1/4 cup canola or sesame oil (not toasted)
Soak the rice in a large bowl with enough water to cover (by approximately 3 liters or 12 cups.) In a separate bowl, soak lentils in (approximately 4 cups) water. Let both bowls stand on counter for at least 5 hours.
Blend both lentils and rice together in a blender until a smooth batter is formed. [*For idli batter, you use the same measurements, but need to blend them separately.] Add Fenugreek if using.
Pour batter into a deep pot, making sure there’s plenty of room for batter to rise up. Now cover and place in an off oven and let stand overnight. Dosa batter is like an old woman and needs a shawl to keep it warm in cooler months- so if the weather is cold, you can help the fermentation by wrapping the covered pot in a towel to keep it extra warm. The warmer it is the better the fermentation. But do not heat!
After a minimum of 24 hours check to see if the batter has risen well/fermented. You’ll know if you see tiny air bubbles on its surface. The longer you wait, the more sour (and tastier) the batter will be.
Stir the batter well and add a tablespoon of salt.
Heat a flat griddle or very large frying pan on medium high heat. Use a rounded ladle to pour just a ¼ cup of batter in the center. Starting in the middle, make concentric circles to spread the batter evenly and thinly to make a crepe-like round. Drizzle an espresso spoon or two of oil around the edges to crisp up the perimeter of dosa.
When air bubbles start to appear and the underside seems golden, take a spatula and lift around the perimeter of the dosa to make sure it’s not sticking, and flip the dosa carefully. Make sure the spatula goes in under the dosa enough so that the dosa doesn’t fold when you try to flip it.
Just heat through for a minute and remove from heat and serve right away with chutney or sambar. The dosa batter will keep in your fridge for up to a week.