In a mixing bowl, mash boiled potatoes and keep it aside.
Now in a mortal-pestal, add green chilli, ginger, garlic cloves and salt. crush into coarse paste. Keep it aside.
Then in a pan, add oil, mustard seeds, cumin seeds, hing and curry leaves. sauté it.
Then add crushed greenchilli-ginger-garlic paste. Sauté for a minute.
Now, lower the flame and add turmeric powder and garam masala. 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.
Make a round shape small size ball from masala and keep it aside.