Soak the Urad Dal over night in Water. 6 hours is more than enough.
After 6 hours, drain the water out and grind the urad dal in a fine paste with some salt and 1/3rd cup of water.
Then add in chopped coriander leaves, chopped ginger, fennel seeds, baking soda and whisk vigorously to make the batter light a fluffy.
In a frying pan or kadai, take oil and heat it.
Wet your palm and take small portions of the batter and drop in the oil o deep fry till golden brown. It is important to keep the temperature at a medium or else the dumplings will brown from outside quickly without cooking in the inside.
This step is important. When you have put in the kadai for heating the oil, instantly also put in a saucepan full of water for heating.
As you fry the dumplings, drop them in the water. Do not boil it. Just trun off the heat for the water once it is hot.
Keep the dumplings in the warm water for 5 to 6 minutes and then with a spatula take them out and place on a place.
Now take the dahi and whisk the dahi propely. Add a little bit of water to thin it.
If your dahi is too sour, add some powdered sugar to it.
The sweet chutney and the green chutney needs to be made in advance and kept.
For the sweet chutney, add the ingredients in a saucepan with a cup of water and boil it till the sugar dissolves and the consistency has become syrupy.
For the green chutney, grind everything in a fine paste with a little bit of water.
Now for assembling, take the dumpling on a plate. Add the yogurt (generous amount) and then drizzle the sweet chutney and green chutney. Finally, sprinkle jeera powder and red chili powder. We Bengalis use bhaja moshla instead of jeera powder. Salt is usually ot required since the green chutney has salt in it. However, if you feel the need, please sprinkle some rock salt.
Serve it immeidately or chill it in the fridge for 1/2 hour and serve.