In a medium deep pan, and add the oil and heat on medium heat for a minute.
Add in the mustard and coriander seeds and let them cook for a few seconds.
Add in the ginger, garlic and chili and cook for a minute.
Add in the onions, turmeric and a little salt and cook for 3-4 minutes stirring occasionally.
Add in the potatoes, some more salt and mix well. Cover and cook on low heat for 15-20 minutes, stirring every 5-6 minutes, until potatoes are well done.
Serve hot topped with chopped cilantro leaves! Serve as part of meal with any lentil curry(Daal), or other soups/stews, Indian bread(Roti) and salad or any indian pickle.(my current favorite is the punjabi raw mango pickle)