In a mixing bowl, mash boiled potatoes and keep it aside.
Now in a pan, add oil, mustard seeds, curry leaves and hing. Sauté for a minute.
Then add ginger, garlic and green chilli paste. Sauté for a minute.
Now, lower the flame and add turmeric powder, garam masala and mix well.
Switch off the gas and add tempering into boiled potatoes.
Also add salt, lemon juice and some coriander leaves. mix well.
Aloo masala is ready. keep it aside.