1. Soak matar dal(yellow split peas)in water overnight or for 5-6 hours.
2. Grind soaked lentils in a grinder and make a smooth paste.
3. Add sodium bicarbonate,salt, assafoetida and nigella into the lentil paste.Beat the paste with your hand for 2-3 minutes till everything is well mixed up.
4. Now heat 4 tablespoon mustard oil in a kadai,add a tablespoonful of lentil paste in it.Once one side turns golden brown and crisp turn the other side.
5. Make all the fritters in batches and set aside.
6. In the meantime, place mustard seeds, green chillies and salt in a blender and blend to a smooth paste.
7. Now add 3/4 cup of water to the mustard paste and strain the liquid to discard mustard skin.
8. Now add 2 teaspoon mustard oil in a kadai,add nigella and slitted green chillies.
9. Then add turmeric powder, cumin powder and red chilli powder into it.Stir for few seconds and then add 1 cup water.
10. When the water starts boiling add mustard paste.
11. Now add all the fritters.Cook for 5-6 minutes in low heat.The gravy should not be very runny but enough to coat the fritters.
12. Then sprinkle chopped coriander leaves into it and give a nice stir.
13. When done switch off the flame and drizzle 1 teaspoon mustard oil on top of the prepared dish.
14. Shorshe Jhale Daler Bora is ready to serve.
15. Serve with steamed rice.