Wash and soak the toor dal for at least 30 minutes. This helps the dal cook faster and become soft.
Add the soaked dal to a pressure cooker along with garlic, turmeric powder, and enough water. Pressure cook for 4 whistles until soft. Mash lightly and keep aside.
Heat oil in a kadai or pan. Add mustard seeds and allow them to splutter. Then add cumin seeds.
Add sliced onions, green chilli, and curry leaves. Saute until the onions turn soft and translucent. Do not brown them.
Add sliced mullangi (radish) and saute for a few minutes.
Add sambar powder and mix well. Cook the radish in the spice mixture until the raw smell disappears.
Add a little water and the sliced tomato. Do not mash the tomato — it will cook and soften naturally as it boils. Cook until the radish is about 60% soft.
Pour in the tamarind extract and allow it to come to a rolling boil. Let it boil well so the sourness blends with the spices and the radish cooks fully until soft.
Add the cooked and mashed dal along with required salt and water. Mix well.
Simmer for 3–5 minutes until the sambar reaches the desired consistency.
Add a pinch of jaggery if preferred and garnish with fresh coriander leaves.
Serve hot with steamed rice, idli, or dosa.
