Drain the soaked chana dal and blend it in a food processor with green chilies and ginger to form a smooth paste. If needed, add a little water to help blend.
Heat 2 tablespoons of oil in a non-stick pan. Add the dal paste and cook on medium heat, stirring continuously, until the mixture thickens and starts to leave the sides of the pan.
Add turmeric powder, cumin powder, coriander powder, and salt. Mix well.
Grease a plate or tray and spread the cooked dal mixture evenly. Allow it to cool and set. Once set, cut into diamond or square shapes.
Heat oil in a frying pan. Fry the lentil cakes until they are golden brown on both sides. Remove and set aside on paper towels to drain excess oil.
In a large pan or wok, heat mustard oil over medium heat. Add cumin seeds and let them splutter.
Add the finely chopped onion and sauté until golden brown.
Add minced garlic and ginger, and cook for another 2-3 minutes.
Add chopped tomatoes and cook until they are soft and the oil starts to separate from the mixture.
Add turmeric powder, cumin powder, coriander powder, red chili powder, and salt. Cook for a few more minutes.
Add water and bring the mixture to a boil. Reduce the heat and let it simmer for 5-7 minutes.
Gently add the fried lentil cakes to the gravy. Let them simmer in the gravy for about 5 minutes, allowing them to absorb the flavors.
Sprinkle garam masala powder over the top and mix gently.
Garnish with freshly chopped cilantro.
Enjoy your meal!