Heat oil in a pan and add cumin seeds. Once the cumin seeds start spluttering add grated ginger and garlic. Saute for a few seconds or until the raw smell of garlic goes away.
Add chopped onion and cook until it becomes translucent.
Next, add green peas, chopped green chilies, salt, all the spices except dried mango powder, Saute for about a minute.
Add 1/2 a cup of water, mix, and cover the pan. Let the peas cook for 4-5 minutes. Fresh green peas will take more time to cook than frozen ones.
Once the peas are cooked, add boiled potato cubes, and dried mango powder. Mix everything. Cover the lid and let it cook for around 2 minutes.
After 2 minutes, switch off the gas. Garnish with chopped coriander leaves and serve hot with Indian bread like roti/ paratha/ puri or dal and rice.