Set Instant Pot to sauté more. Add oil to the pot.
Add mustard seeds to hot oil and let them temper. Once finished, add curry leaves, grated garlic, and ginger. Let it brown slightly.
Add in onions and sauté with spices and oil. Let it brown.
Add in tomato paste, vindaloo seasoning, and cayenne. Continue to sauté for 1-2 minutes.
Add in lamb, potatoes and salt and pepper and brown the meat.
Add in water once the meat has browned on the outside and stir everything well. Water should slightly be covering the lamb (not fully submerged since the lamb will release some water when it cooks).
Close the lid on the instant pot and set to pressure cook on high for 20 minutes. Set pressure valve to sealing!
Once finished, let the pressure naturally release.
Open the instant pot and add in a can of coconut cream and give it a good stir.
Then, taste and adjust seasonings as needed (salt, spice).
Garnish with cilantro and lemon juice (optional) and serve immediately!