Firstly take 1 cup sona masuri rice, 2 tablespoons urad dal (optional) and 8 to 10 methi seeds (optional) in a pan or bowl. You can use any regular variety of rice.
Take ½ cup thick poha in another bowl. Rinse the poha also.
Now add the poha in the bowl which has the rinsed rice, urad dal and methi seeds. Also add 1.5 cups water for soaking and soak for 4 to 5 hours. You can also soak everything in curd+water solution if you plan to soak and ferment for less time
Before grinding, take ½ cup fresh curd (dahi or yogurt) and 1 to 1.25 cups water in a bowl.
Mix very well with a spoon or a wired whisk to get a uniformly mixed solution.
Drain the rice, poha and urad dal very well and then add them in a grinder jar. Also add the curd solution.
Grind till smooth or till you get a fine grainy texture of rice in the batter. You can grind batter in batches depending on the size of the grinder jar.
Then add ½ teaspoon sugar and ⅔ to ¾ teaspoon rock salt or add as required. Mix very well. Cover and let the batter ferment overnight. You can also keep the batter to ferment for less time.
The fermented dosa batter next day.
Heat a griddle or a tawa. Keep the flame to a medium-low or medium. Spread some oil or ghee on the tawa.
Now take a ladle full of the dosa batter and pour it on the hot tawa. Don’t spread too much as then the dosa breaks. Make small dosas.
Cover with a lid and cook curd dosa on medium-low or medium flame.
When the top side gets cooked and the base is golden, this means the curd dosa is done. You can spread some oil or ghee if you want on the top.
Remove with a spatula. Make all sponge dosas this way.
Serve soft dosa hot or warm with coconut chutney or with potato sagu or veg sagu.