Prepare Masala. Turn on the Instant Pot and click SAUTE mode. Once hot, add oil and let it heat up. Then add cumin seeds and saute for 40 seconds. Add ginger, garlic, and green chilies and saute for a minute. Then add onions and season with salt. Saute for 5 minutes or until golden brown. This is where the flavor lies, so be patient. Once the onions are slightly caramelized, add pureed fresh tomatoes and stir for a minute.
Add Spices. Now add the powdered spices - turmeric powder, coriander powder, red chili powder, Kashmiri red chili powder, and salt. Stir. Cover the Instant Pot with the glass lid and cook for 5-6 minutes. Once done, the oil should separate from the tomatoes and you should have a paste-like consistency. Make sure you deglaze the pot to avoid any sticking.
Add Potatoes & Peas. Add potatoes cut into 1-inch cubes and stir everything for a minute. Click CANCEL on the Instant Pot. Add water and frozen green peas that have been rinsed and drained. Stir well. Cover the Instant Pot with the knob set to SEALING mode. Click HIGH PRESSURE for 2 minutes. Once the cooking time has been completed, manually release the pressure after 7 minutes. Your Aloo Matar is cooked.
Garnish. Garnish with garam masala and fresh cilantro. Stir. Wait 15 minutes before serving so the flavors can marry, and the gravy will thicken. Enjoy with hot roti or paratha.