Peel and discard the large seeds or soft part of the doodhi. Dice doodhi into medium cubes of an equal size to ensure even cooking. Keep the cubed doodhi aside.

Heat some oil in a heavy-bottomed kadai and add mustard seeds. Once the seeds splutter, add the cumin seeds, hing, and curry leaves, then mix briefly.

Add the soaked chana dal to the oil with the spices, then add turmeric, salt, and water (about 200 ml), and put the lid on. Cook on a low flame until the dal is cooked but retains its shape.

Once the dal is partially cooked, add the diced doodhi, coriander powder, chilli powder, and garam masala, mixing everything well without breaking the vegetable pieces.

If you wish, you may add a little more water to the pot, cover it, and cook over medium-low heat until the doodhi becomes tender and the chana dal softens. The cooking process should be punctuated with stirring to prevent adding too much water. 

You should add kokum petals and jaggery to the shaak. Subsequently, simmer the dish uncovered for several minutes to balance the sweet and sour flavours. At this point, you may taste the dish and add salt, chilli, or jaggery if needed. 

Once the cooking is done, you may turn the cooker off and leave the shaak for a while. You may decorate the dish using chopped coriander right before serving.