Take bananas with salt & sugar in a bowl and mash them well.
4 overripe small bananas, ¼ teaspoon salt, 2 tablespoons sugar
Add all ingredients except besan, maida & oil and combine everything well.
¼ cup curds, 1 ½ tablespoons butter, ½ teaspoon jeera, ¾ teaspoon baking soda
Add besan & maida & knead to a firm dough. No water to be added.
1 teaspoon besan, 1 ¾ cups maida
Oil the surface of dough & set aside covered in a warm place for 6-8 hours or overnight.
¾ teaspoon cooking oil for the dough
After the resting hours, heat oil in a deep frying pan on medium heat.
Cooking oil for deep frying
Knead the dough for a minute, make lemon sized balls and roll out approx. 4mm thick buns. It should be double the thickness of puri. See note 3.
Once the oil is hot, reduce the heat to medium, add the buns, keep it dipped in oil by gently pressing with a ladle. The buns puff up & rise.
Flip and cook the same way on the other side till they turn golden on both sides.
Roll and fry the buns one by one only on low to medium heat which ensures that they are well cooked from the inside.