Boil potatoes in their jackets. Peel them and mash coarsely with a fork or hand masher.
Heat the oil in a 10-12 inch skillet over medium heat. When hot, first put in it the asafetida; after it has sizzled for a few seconds, add the cumin and mustard seeds; then in 10 seconds or so, the red pepper(s). Use 1 for mildly hot, 3 for very hot. When pepper changes color (1 to 5 seconds), put in the chopped onions and turmeric. After the onions have cooked 3 to 5 minutes and turned brown at the edges, put in the mashed potatoes, salt, garam masala and lemon juice. Fry, stirring and mixing, for 5 to 7 minutes.
To serve: Place in a warm dish and serve with Indian bread or remove whole red pepper and serve as an appetizer on top of Melba rounds.
An Invitation to Indian Cooking by Madhur Jaffrey
Note 1: the Indian name of this dish is Pyazwale Sookhe Aloo. Note 2: use a salt-substitute instead of salt Note 3: I've made this without the asafetida because I don't know where to find it.