Heat butter in 12-inch skillet over medium-high heat until sizzling. Add chicken; cook 3-5 minutes or until chicken is browned. Turn chicken; add garlic and ginger. Continue cooking 3-4 minutes. Add diced tomatoes, cumin, garam masala, paprika, salt, turmeric and cayenne pepper. Reduce heat to low; simmer 30 minutes. Remove chicken. Puree sauce in blender or with immersion blender until smooth. Stir in 1/4 cup whipping cream and return chicken to pan, heating through if needed. Sprinkle with cilantro. Serve with cooked rice and naan bread.