Heat mustard oil in a pan over high heat.
Once the oil is hot, add the peeled potatoes to the pan and fry until they turn brown from all sides, stirring frequently. Remove the fried potatoes to a plate and keep them aside.
Reduce the heat to medium. Add asafetida and green chilies to the same oil and let them crackle for 4-5 seconds.
Add bay leaves, cloves, and black peppercorns, and let them crackle for 4-5 seconds.
Now add onions and fry until they turn light brown in color, stirring frequently.
Add ginger-garlic paste and fry until onions are nicely browned. Stir frequently.
Add tomatoes to the pan and cook for a minute. ThenAdd yogurt and cook for another minute, stirring continuously otherwise the yogurt might curdle.
Now add coriander powder, turmeric powder, chili powder, cumin powder, garam masala powder, salt, and sugar, and fry until the oil starts to separate from the sides. Then add little water if the masala is getting too dry.
Add the fried potatoes and a cup of water to the pan and mix well. Bring the curry to a boil. Reduce the heat to low.
Cover the pan with a lid and cook for 8-10 minutes. Add more water if the curry is too dry and bring it to a boil.
Check for salt and add more if needed. Garnish with cilantro and serve hot.