This curry is very simple and is perfect for those days when you need something warm and comforting. It is slightly spicy and the gravy is nice and thick with a slightly sour element from the addition of tamarind. You can serve this with rice or chapatis/parathas. It is even delicious served in a bowl with some crushed potato or cassava/crisps.
Peel and cube the potatoes, then boil until tender and drain off the water.
In a pot, heat the oil and then add the chopped onion and fry until they soften and just start to turn colour. Then add the garlic paste, chilli powder, turmeric powder and curry powder. Stir them in quickly and then add the fresh grated tomato, chopped green chillies and tomato paste. Cook until the tomato mixture thickens, then add the boiled potato cubes, some salt, the tamarind sauce and just enough water to barely cover the potatoes. Mix and turn the heat down. Cover the pot and allow the curry to simmer for 5 minutes. During this time, you can open the pot and mash up a few pieces of the potatoes just to help thicken the sauce and give it a rich gravy.
Finally squeeze in the lemon juice and stir it in. Taste and adjust for salt. Turn the heat off and serve!