Turn on the SAUTE mode on the Instant Pot and heat two tablespoons of oil to sear the chicken pieces. Be careful not to overcrowd or overlap the chicken, and cook it on high heat for 2 minutes on each side.
Once all the chicken pieces are cooked, remove them from the Instant Pot and set them aside.
Turn off the Instant Pot and add butter. The residual heat is enough to melt it.
Add the grated garlic and onions, turn on the SAUTE mode again, and saute the onions for 3-4 minutes till translucent.
Add cashew paste, tomato puree, Kashmiri chilli powder, ketchup, and salt. Mix well and let this simmer for 5 minutes. Use a hand blender to grind the gravy further to make it smooth. This step is optional.
Add the chicken pieces along with all the juices and mix well.
Pour in ¾ cup of water, put the lid on, turn the valve to sealing, and pressure cook on MANUAL for 8 minutes. After 10 minutes, release the pressure manually.
Turn on the SAUTE mode, add crushed kasuri methi and garam masala and mix well. Simmer for a minute or two and mix in the cream. Top with some chopped coriander and serve hot.