Stir together spice blend in bowl.
Melt butter in a 12" nonstick skillet over medium heat. Add the onion and cook, stirring frequently, until the pieces just begin to turn gold, about 5 minutes. Add the garlic, tomato paste and spice blend, and cook for 1 minute, stirring constantly to prevent burning.
Add the tomato sauce and diced tomatoes and stir well. Add the chicken pieces, spoon the suace over the top and bring to a simmer. Turn the heat to low and cook, uncovered, until the chicken is warmed through and the sauce is flavorful, about 10 minutes.
Stir frequently. Remove chicken to a serving dish and cover to keep warm.
Shake any excess water from the peas. Add peas and cream to the sauce in the pan, stir well and heat through. Do not boil. Spoon the sauce over the chicken. Serve with rice and warmed pita bread.