In a large skillet, add 1 tsp of oil and heat at medium. When the oil is hot, add mustard seeds and fennel seeds and let them sizzle and start to pop. half a minute. Use a lid if the mustard seeds start to explode out of the pan.
Add garlic and mix in. Cook for 1 minute. Add potatoes and mix to coat. Add salt and water and mix in. Cover and cook the potatoes for 20 to 25 minutes or until tender. Stir once or twice in between and add more water to de glaze if needed.
In a small bowl, mix the coriander powder, garam masala, cayenne, turmeric and rice flour. Add this to the potatoes and mix well to coat. Add 1 tsp oil and mix well so the potatoes are well coated with the spices and flour. Cook for 2 minutes so the spices and flour get cooked.
Taste and adjust salt and spice. Garnish with cilantro. Serve hot as a side with dals, rice or flatbread. or fill a sandwich with these potatoes, tomato slices and cheese, grill and serve.