For gravy: fry onion and garlic in oil till oil separates. Add the chilli powder and turmeric. Wait till oil oozes. Add rest of the spices and tomato puree. Fry till oil separates. Add hot water for the desired consistency. Boil for a few minutes.

For the potatoes : Cook potatoes in a pot (NOT THE COOKER). They must be thoroughly cooked, but not overcooked till cracking point. Peel and cut them into large chunks. Combine chilli powder, salt, garam masala and turmeric powder with garlic paste.