Clean, wash and soak the chana dal for 5-6 hours. Soaking time is not included in the total cooking time.
Wash, peel and cut the potatoes into thick cubes. Keep them in water till required, else it will turn dark.
Drain the dal and place it in the grinder. Add salt, sugar, cumin powder, turmeric powder, grated ginger, green chilli, fresh grated coconut and water. Grind it to a smooth fine paste.
Pour the ground paste into a greased plated. Steam on high heat for 15-20 minutes or until firm and cooked. Check with a knife or skewer; if it comes out clean means, it is cooked. Remove, cool it completely and cut it into cubes or diamond-shaped pieces.
Heat mustard oil in a pan or kadhai. Shallow fry the pieces till they turn lightly golden brown and cooked from both sides. Transfer on a tissue paper-lined plate and keep it aside.
Heat mustard oil in a kadhai or pan. Add black cardamom, cardamom, cinnamon, bay leaf, cloves, dry red chilli, hing and cumin seeds. Let it crackle.
Add potato cubes and stir it well. Add turmeric powder and mix it well. Cook potatoes in the oil for 2-3 minutes on medium flame.
Add grated ginger, green chilli (optional) and freshly grated coconut and cook it for 3-4 minutes on low flame.
Add the chopped tomato, cumin powder, coriander powder, red chilli powder and salt. Stir it well and add green chilli. Cook it till the oil starts separating from the tomatoes and spice mixture. It will take around 8-10 minutes. Keep stirring to avoid burning.
Once the oil is separated from the tomato and spice mixture, add sugar, aromatic garam masala powder and 2 cups of water. Let it come to a boil, then turn the flame to low.
Add the fried chana dal pieces to the tomato and spices curry. Let it simmer for 4-5 minutes. Adjust the consistency and seasoning.
Add coriander leaves and mix them well. Switch off the flame.
Bhapa dhokar dalna is ready to serve.