Cut the chicken pieces into quarters.
Put tomatoes, jalapeno and ginger in a blender or food processor and blend to a fine puree.
Add butter to pressure cooking pot, select Browning. When butter is melted and foam begins to subside, add the chicken pieces, a few at a time, and sear until they are nicely browned all over (about 2-3 minutes per batch). Remove them with a slotted spoon into a bowl and put aside.
Add ground cumin and paprika to the butter in the pot and cook, stirring rapidly, for 10-15 seconds. Add the tomato mixture, salt, cream, yogurt and chicken pieces (with any juices that have accumulated in the bowl) to the pot. Gently stir the chicken to coat the pieces. Cover and lock lid in place. Select High Pressure and 5 minutes cook time. When timer beeps, turn off and use a natural pressure release for 10 minutes. After 10 minutes use a quick pressure release to release any remaining pressure.
Stir in the garam masala and roasted cumin. Whisk together cornstarch and water in a small bowl. Stir in to sauce in the pot. Select sauté and bring to a boil. Turn off pressure cooker and stir in minced cilantro.
Serve with rice and naan.