Wash the kovakkai well and cut them length wise into long pieces. Keep aside.
Heat oil in a kadai or pan. Add mustard seeds and allow them to splutter. Add broken urad dal and jeera. Saute for a few seconds until aromatic.
Add chopped onions, curry leaves and garlic. Saute until the onions turn soft and translucent.
Add chopped tomatoes along with turmeric powder and salt. Cook until the tomatoes become soft and mushy.
Add Kashmiri red chili powder and coriander powder. Saute well until the masala thickens slightly and the raw smell disappears.
Add the cut kovakkai and mix well so the masala coats evenly.
Add water as needed, cover and cook on medium flame until the kovakkai becomes soft and well cooked. Stir occasionally in between.
Once the kovakkai is cooked, increase the flame to medium-high and saute until the thokku becomes thick, nicely roasted and reaches a rich color.
Garnish with freshly chopped cilantro and serve hot with rice, sambar, rasam, roti or chapati.