Add Oil in a pan and heat it on high flame preferably for about 2 minutes.
Add Cumin Seeds and Asafoetida. Let them fry for 30 seconds on high flame or until Cumin seeds turn dark brown in colour.

Now, is the time to add Onion and fry it for about 1 minute. The Onion needs to be fried else it would feel raw while eating.
Add Potatoes and Green Chilies Slit them into 2 pieces before adding. Mix them well with Onions. Cook on medium flame for 2 minutes. Stir occasionally.
Turn the stove to low flame and add the spices at this point.
Sprinkle Salt, Red Chilli, Coriander, Mango Powder, Turmeric Powder. Mix well.

Cover the pan with the lid and cook until potatoes get soft or approximately  10 minutes
Stir occasionally to avoid burning.
You can pork the Potatoes with the knife or spatula to check their readiness after 10 minutes of cooking. If they cut easily with spatula they are ready.
Sprinkle Garam masala and mix well. Switch Off the stove.
They are now ready to serve hot.