START: On a 6 quart Instant Pot, select More/High Sauté. Add the oil and onion, then cook, stirring occasionally, until the onion begins to brown, about 5 minutes. Add the ginger and garlic, then cook, stirring, until fragrant, about 30 seconds. Stir in the paprika, turmeric, garam masala and cayenne. Pour in 1 1/2 cups water, scraping up any browned bits. Add the potatoes and 1 1/2 tsp salt; stir to combine, then distribute in an even layer. Add the tomatoes with their juice in an even layer on top of the potatoes; do not stir.
Fast: Press Cancel, lock the lid in place and move the pressure release valve to Sealing. Select Pressure Cook or Manual; make sure the pressure level is set to High. Set the cooking time for 4 minutes. When pressure cooking is complete, quick-release the steam by moving the pressure valve to Venting. Press Cancel, then carefully open the pot.
FINISH: Select More/High Sauté and cook, stirring often, until a skewer inserted into the potatoes meets no resistance and the sauce clings lightly, 3 to 4 minutes. Press Cancel to turn off the pot. Using potholders, carefully remove the insert from the housing. Let stand for 10 minutes. Stir in the peas and cilantro, then taste and season with salt and pepper.
Notes
Don’t forget to thaw the peas before use. They are added off heat, when cooking is complete, so if they are still frozen, they will cool the curry. After adding the tomatoes, don’t stir them into the potato mixture; if mixed in, they tend to sink to the bottom of the pot and burn.