Scrape the drumsticks, wash and chop them in equal sized long pieces.
Peel potatoes and cut them in thin slices and soak them in water.
Crush the garlic cloves (with skin on).
Parboil the drumbsticks. Dissolve tamarind in little warm water and mash well to extract the pulp. Discard the seeds.
Grind coconut with little warm water to make a fine paste.
Heat oil in pot/kadhai. Toss the garlic in hot oil and let them brown.
Add onions and stir fry till lightly colored. Drain water from potatoes and add to the the onions.
Add ginger-garlic paste, turmeric powder and red chili powder. Saute for a few minutes.
Add sufficient water to the gravy. Cover and let potatoes cook.
Add the drumbsticks and let it simmer till cooked.
Add the salt, tamarind pulp and coconut puree. Cover and simmer till aroma arises.
When ready to serve, garnish with coriander leaves.