Mix together the marinade ingredients in a large bowl, add in the chicken breast cubes, and marinate for 1 hour. Thread the cubes onto skewers and either broil or barbecue the chicken until slightly blackened in spots and the inside is no longer pink.
In a large skillet, sauté onion until golden and add the remaining sauce ingredients except the cream. Cook, covered for 10 minutes, add the heavy cream and cook uncovered for another 10 minutes until sauce is thick and creamy.
Add cooked chicken from the skewers and simmer for 10 minutes. Serve with cilantro for garnish.