Add diced potatoes, carrots & sliced onions to the instant pot.
Add 1 cup of water also to the instant pot.
Also add salt and the spice powders (other than black pepper powder), mix everything well.
Add the tamarind, stir in to mix with the water and vegetables.
Also add the oil, stir the contents and close the instant pot with lid in sealing postion.
Cook in high pressure for 5 minutes. Do a natural pressure release for about 12 minutes, then do a careful and gradual manual pressure release.
Once the pressure is all released, carefully open the lid.
Stir the contents and gently mash a few cooked potato pieces.
Add the remaining 1 cup of water and also the black pepper powder (if using), mix the contents well and simmer the contents (using saute function) for a couple of minutes (stir in between).
Finally add the coconut milk, stir into mix with the curry, serve the delicious potato carrot curry hot with rice or Indian breads like chapathi, poori, naan bread etc.