Potatoes With Onions

• 6 potatoes
• 1 onion coarsely (chopped)
• 1/8 asafetida (ground)
• 1/8 lump asafetida
• 75 ml vegetable oil
• 30 ml lemon juice
• 12 ml black mustard seeds (whole)
• 3 gr salt
• 3 gr garam masala
• 1 gr cumin seeds (whole)