In a bowl, stir together the spice rub ingredients.
Add the lamb and turn to evenly coat. Set aside at room temperature for 20 minutes or refrigerate for up to 3 hours or even overnight for the best flavors.
Select the high Saute setting on the Instant pot and and heat the oil.
Add the onions and cook until translucent, 5 to 7 minutes.
Press the Cancel button to turn off the Instant Pot. Add the marinated lamb and stir to combine.
Pour in the water and stir well with a wooden spoon, nudging loose any browned bits from the pot bottom.
Secure the lid and set the Pressure Release to Sealing. Set the cooking time for 40 minutes at high pressure.
Let the pressure release naturally for 15 minutes, then move the Pressure Release to Venting to release any remaining steam.
Open the pot and stir in the tomato paste and garam masala.
Select the high Saute setting and cook until the curry comes to a gentle boil and thickens slightly, about 5 minutes.
Press the Cancel button to turn off the Instant Pot.
Spoon the curry onto plates, sprinkle with the cilantro, and serve with parathas.
DONE!