Wash the daal and preferably soak for at least 30 minutes. In a small pot, add the channa ki daal and plenty of water. Bring to a boil. Reduce the heat to medium-low and boil until tender.
While the daal is cooking, in a medium sized pot, add spinach, tomatoes, coriander, cayenne pepper, turmeric, ginger garlic paste and salt. Cook on medium heat until all the water is gone. When the daal is tender, drain and add to the spinach mixture. Once the spinach mixture is dry add the green chillies.
For the baghar, heat the oil in a small skillet. Add the cumin, nigella seeds and mustard seeds. After about 30 seconds add the dried red chillies. Once the chillies have puffed up and the mustard seeds are popping add all at once to the spinach mixture. Add the lemon juice, stir and enjoy!