Chop the drumstick into 1 1/2 inch pieces. Slice the radish into 1/2 inch thick pieces.
Soak tamarind in 1 cup of water and get the juice.
Pressure cook the pigeon pea along with cumin seeds, 1/4 teaspoon (tsp.) fenugreek seeds, turmeric powder, asafoetida powder, garlic for 4 to 5 whistle. Once the pressure is release mash the pigeon pea.
Now add chili powder, salt as needed to the cooked pigeon pea and mix well.
Now add drumstick, tomato, onion, radish to the cooked pigeon pea.
Now add water to the pressure cooker until the vegetables sink. Pressure cook this for 20 minutes without the whistle.
Now add the tamarind juice and cook for 5 minutes or until the raw smell of tamarind is gone.
In the mean time heat oil in a pan. add mustard seeds, cumin seeds, curry leaves, dry chili. Once the mustard seeds stop splattering add this to the boiling sambar.
Remove sambar from heat then garnish with coriander leaves and serve.