Add oil to the insert of a 6 or 8 quart Instant Pot. Press the saute function, and heat the oil. Once hot, add garlic and ginger and cook while stirring, until fragrant, about 1 minute.
Add tomato paste, tomato puree, garam masala, turmeric, salt and cumin and cook for 3 minutes, stirring occasionally. Shut off the saute function and add in cinnamon stick, chicken stock and stir together. Place the chicken breasts inside.
Arrange a 2.5-inch trivet over the chicken and place a 7-inch oven-safe bowl on top. Add the rice and water to the bowl. Secure the lid and move the steam release valve to Sealing. Cook on manual high pressure for 12 minutes. Move the steam release valve to venting to quickly release the steam pressure. When the floating valve drops, remove the lid.
Remove the rice and the trivet. Fluff the rice, cover to keep warm and set aside. Remove the chicken and dice into bite-sized pieces and set aside.
Press the saute function and whisk in the butter and cream and cook until slightly thickened, about 2 minutes. Add the diced chicken back to the pot to heat through.
Serve the chicken with the rice, and garnish with cilantro, if desired.