Add tapioca pearls, flattened rice, fenugreek seeds and give it another wash. Drain.
Soak the above ingredients in plenty of water for 5 hours or overnight.
After soaking, drain the water.
Add the soaked ingredients into a blender along with chopped banana.
Add ¼-½ cup water(or as needed) to grind the ingredients into a smooth batter. The batter should not be too watery, something similar to a thick cake batter/ regular dosa batter.NOTE: The rice should be smooth, no grits should remain.
Transfer the batter into a container. Cover and let it rest in a warm place to ferment for 8-12 hours. NOTE: Tips to ferment batter in winter in 'notes' below.
If not using immediately after fermentation, the batter can be refrigerated.
Preparing dosa
Add salt to the fermented batter.
Mix gently to incorporate the salt. Add water (only if needed) to make a batter that is pourable, not too thick, not too thin something similar to a cake batter/regular dosa batter. NOTE: Please check the video for a visual guide.
Heat a cast iron griddle/frying pan on medium-high heat. NOTE: The pan should be hot and you should be able to see gentle fumes when you grease it. Adjust heat as needed to maintain the temperature.
Grease the pan/griddle with oil/butter/ghee
Pour a ladleful of the batter and spread it around slightly.
Cover with a lid and cook for 30 seconds or until the top looks cooked and no whitish spots remain.
Drizzle ¼-½ tsp of oil/ghee on top of the dosa.
With a thin spatula, release the dosa from the pan.
The dosa can be flipped to brown the top or you can choose to serve it without browning the top.
Grease the cast iron griddle/pan lightly with oil/ghee before making the next dosa.
Serve dosa with coconut chutney, honey, maple syrup or yogurt on the side.
Video
Notes
I have used regular long grain rice, sona masoorie rice, idly rice, dosa rice with good results. I am unsure if this recipe will work well with a very sticky variety of rice.
Flattened rice and tapioca pearls help in making the dosa extra fluffy and airy. They are optional. I have made this dosa plenty of times with only rice and bananas, please find the picture in post.
As long as the batter is not too thick or too thin, it will work just fine.
How fluffy and airy the dosa is, depends on the fermentation.
After fermentation, it is normal for the top of the batter to look brownish, due to the oxidation of bananas.
It is important to cook dosa covered, to avoid any whitish streaks that may otherwise remain.
Use oil instead of ghee to make the dosas vegan.
Fermenting batter in winter
Preheat the oven for 1 1/2 - 2 minutes. Turn the oven off and place the batter in. You can choose to turn on the oven light.
Ferment the batter in an instant pot, Yogurt mode on low.
Add a spoonful of fermented idly/dosa batter from a previous batch.
Add half-one teaspoon of sourdough starter/discard to boost fermentation.
Banana dosa without fermentationDosas can be made without fermenting, they will still be soft but not very airy. If making without fermentation, consider adding 1/4 cup of fresh/frozen coconut while blending the batter.