Turn your Instant Pot to the sauté setting.
Add the butter and cook until the butter has melted. Add the garlic and ginger and sauté for another minute or until the garlic becomes aromatic.
Add the tomato sauce and tomato paste and stir together. Add in the garam masala, coriander, cumin, paprika, turmeric and salt, stir together one more time and let cook for about 3 to 5 minutes.
Add in the seasoned/marinated chicken thigh cubes, water and stir everything together. There should be enough liquid in the pot to cover the chicken, so add more water if needed.
Close the lid and set the Instant Pot to the Poultry setting and set the timer for 5 minutes.
Once the Instant Pot cycle is complete, you can wait until the natural release cycle is complete, should take about 10 minutes, or you can do a manual release. Carefully unlock and remove the lid and switch the Instant Pot to the sauté setting (with the lid OFF).
Add in the heavy cream, mix together and let simmer for about 5 minutes, stirring occasionally. The sauce should thicken and reduce a bit.
Serve over rice and garnish with fresh parsley. Enjoy!