In a large pan saute onion, ginger and jalapeno pepper in oil.
Stir until onion is lightly browned about 5 minutes.
Add in garlic, garam masala and chili powder (if desired).
Saute for 2-3 minutes.
Put mixture into blender.
Add in tomato paste and chicken broth and pulse until smooth.
Put mixture back in pan and add in half and half.
Bring to a boil and simmer for 5-10 minutes.
In another pan heat 1 tbsp butter over high heat and add in chicken that has been salted and peppered.
Cook until chicken is no longer pink.
Add in sauce and stir. Cook for 3-4 more minutes.
Add in 3 tbsp butter and stir until melted.
Serve over rice. Squeeze lime juice over mixture and garnish with chopped cilantro.