Boil potatoes untill cooked and not mushy.
Heat oil in a thick bottom pan or kadhai. When hot, add the tempering ingredients – raw peanuts, chana dal, udad dal, mustard seeds, and cumin seeds. On medium flame, saute till dals change to light golden color.
Add dry red chilly, curry leaves, and a pinch of hing. Saute till curry leaves turn crisp. Next, add crushed ginger and green chilies. Fry for few seconds till aromatic. Do not fry for a long time, else it will taste bitter.
Add frozen green peas and sliced onions. Saute till the onion turn soft or transparent. Add turmeric powder and salt. Mix very well.
Add mashed potatoes and mix well with the spices. With the back of your spatula, gently mash the potatoes. Saute/bhuno the potato masala for at least 5mins. Check for salt and add if needed.
Lastly, add chopped coriander leaves and give a good mix. Potato masala is ready to enjoy.