Fry the potatoes in hot oil until golden. Set aside.
Leave 4 tbsp oil in the pan. Fry onions until golden.
Add ginger and garlic, followed by turmeric and chilli powder.
Return the potatoes to the pan and pour in water.
Cook for 5 minutes over a gentle flame. Sprinkle in sugar and pour on vinegar.
Heat 2 tbsp of oil in a separate pan. Add red chillies, mustard, cumin and nigella seeds (kaloongi / onion seeds).
Stir and fry for 20 seconds. Pour over cooked potatoes before serving.
Key Ingredients: potatoes, onion, vegetable oil, red chilli, turmeric, ginger, garlic, vinegar, mustard seeds, sugar, cumin seeds, onion seeds