In the inner cooking pot of the Instant Pot, add the tomatoes, garlic, ginger, turmeric, cayenne, paprika, one teaspoon of garam masala, cumin, and salt. Mix thoroughly, then place the chicken pieces on top of the sauce.
Lock the lid into place. Select Manual or Pressure Cook, and adjust the pressure to High. Cook for ten minutes.
When the cooking is complete, let the pressure release naturally. Unlock the lid. Carefully remove the chicken and set it aside.
Using an immersion blender in the pot, blend together all the ingredients into a smooth sauce. Let the sauce cool for several minutes.
Add the butter cubes, cream, remaining teaspoon of garam masala, and cilantro. Stir until well incorporated. The sauce should be thick enough to coat the back of a spoon when you’re done.
Remove half of the sauce and freeze it for later, or refrigerate for as long as three days.
Add the chicken back to the sauce. Preheat the Instant Pot by selecting Sauté and adjust to Less for low heat. Let the chicken heat through. Break it up into smaller pieces, if you like, but don’t shred it.
Serve over rice or raw cucumber noodles.