Heat oil in a wide pan. Add the fennel seeds and allow them to splutter.
Add the sliced onions, curry leaves, crushed ginger, and crushed garlic. Sauté until the onions become soft and translucent.
Add the cubed tomatoes and give everything a quick stir.
Add the turmeric powder and salt. cook until they become soft and mushy.
Then add the Kashmiri red chilli powder and sambar powder. Sauté until the oil begins to separate from the masala.
Add the brinjal, drumsticks, and potatoes. Mix well until the vegetables are evenly coated with the masala.
Pour in enough water to immerse the vegetables.
Cover and cook until the vegetables are tender and the raw smell of the spices disappears.
Meanwhile, grind the grated coconut, roasted gram, green chilli, and fennel seeds with enough water to make a smooth paste.
Add the ground coconut paste to the kuzhambu and mix well.
Add hot water as needed to adjust the consistency. Simmer for another 5 minutes.
Garnish with freshly chopped cilantro and serve hot with steamed rice, chapati, or dosa.