Wash the toor dal well and soak it in water for at least 1 hour.
Transfer the soaked dal to a pressure cooker. Add chopped tomato, garlic cloves, turmeric powder, required salt, and enough water. Pressure cook until the dal becomes soft and mushy. Mash lightly and keep aside.
Heat oil in a pan over medium flame. Add cumin seeds and allow them to splutter.
Add sliced onion and broken red chillies. Saute until the onions turn soft and translucent.
Add the cleaned vendhaya keerai to the pan. Mix well and cook for 2–3 minutes until the greens wilt and soften.
Add the cooked toor dal to the pan and mix everything well.
Check salt and adjust if needed. Add a little water if the kootu is too thick.
Let the vendhaya paruppu kootu simmer on low flame for 5 minutes.
Switch off the flame once the kootu reaches a creamy, well-blended consistency.