Add toor dal to a pressure cooker, wash it thoroughly and cook the dal for 2-3 whistles adding 3 cups of water.
Meanwhile, soak a big lime size tamarind. When soaked, squeeze the juice and filter the pulp.
Mash the dal to smooth texture with a laddle. When the dal is perfectly cooked, you will get a nice smooth dal when mashed.
Add the tamarind juice to the dal and mix well without any lumps and keep aside.
Take a vessel, add oil. When heated, add mustard seeds, cumin seeds, methi seeds, hing, dried red chilies, crushed garlic cloves, and curry leaves.
When the tempering is nicely fried, add onions, green chilies, and saute them until they are translucent.
Add tomatoes and cook for a minute.
Now add the drumstick pieces, turmeric, and salt. Cook until the drumsticks are cooked perfectly. When you hold the drumstick and press gently, it should be smooth and tender.
Add the dal mixture prepared earlier, chili powder, mix well. If the mixture is thick add 1 or 2 cups of water to get the consistency. Boil for 5-8 mins.
Now add 2 tablespoons of sambar powder.
Boil the sambar on a medium flame for 3-4 more minutes. Check the taste and adjust salt or chili powder as per your taste.
Serve sambar hot with rice.