First wash the lotus stem well and cut them into pieces. Cut the potato in cubes too as shown below. Now put them into a pressure cooker, add some turmeric powder and salt and pressure cook them until 5 to 6 whistles. Remove them from the cooker and keep it aside.

Now let's come to chana dal. First soak the chana dal for about 2 hours or overnight. Then pressure cook them with some salt and turmeric powder until 3 whistles on medium flame. Now add this with the boiled lotus stem mixture (shown in step 1)

Now heat a pan. Add sufficient amount of mustard oil for frying the masala. Then add jeera, kalounji, a bay leaf and dried red chilli. Let them splutter. Then add chopped tomatoes, onion slices, slit green chillies and crushed garlic pods. Add little salt and fry them for about 2 minutes.

Until the masala is getting cooked, in a bowl, add all the dry masalas like turmeric powder, cumin powder, coriander powder, red chilli powder, sugar, some salt and curd. Mix everything well. Now add this mixture into the fried masala. Let it cook on a low flame.

Fry the masala until oil starts releasing from it. Then add the boiled lotus stem and dal mixture in it. Combine everything well. Add half a cup of lukewarm water; you can add the water as per your consistency of gravy. Then add little salt and mix everything well. Now cover the lid and let it cook on a low flame for about 10 minutes.

Finally sprinkle some garam masala powder, a tsp of ghee and some chopped coriander. Mix everything well. Turn off the flame. Your mulun cholar dal is now ready to serve. Serve it hot with some steamed rice or chapatis.