On medium heat, in a saucepan, heat the oil, add the chopped onions, and sauté till golden.
Add the cumin seeds and mix well with the onions. Once the aroma of the cumin comes through (after about 1 minute), add the ginger and garlic and sauté for a minute.
Stir in the green chillies, turmeric and asafoetida.
Add the potatoes, water, salt and pepper. Cover, turn the heat to low and cook for 10 minutes till tender.
Add the peas and tomato sauce, cover again and cook for another 5 minutes.
Turn off the heat and garnish with garam masala and chopped cilantro/coriander leaves. Serve with warm roti, or in dosa.
Notes
This is a dry aloo matar recipe. To make it with gravy, add an extra cup of water before adding to the pan.