Microwave potatoes for around 4 minutes till cooked. This is my shortcut method to cut down cooking time. If you do not want to use the microwave you can boil potatoes on the stove top, or in a pressure cooker.
Heat oil in a pan. Add seasoning ingredients. When the mustard splutters. Add onions, chopped ginger, and green chilli. Fry for a few minutes till opaque.
Add turmeric powder and salt. Mix well.
Add the boiled potatoes with about 1 cup of the cooking water. Cover and cook for about 10 minutes.
Use a potato masher or fork to mash the potatoes. If you like it chunky you can leave a few pieces of potato unmashed. Adjust the salt.
Garnish with chopped coriander leaves.
Notes
If you do not have curry leaves or split urad dal, you can skip them. It will still be just as good.
I did not have cilantro for garnishing, so you can just leave it out like I did.