In a bowl, combine all the marinade ingredients. Add chicken pieces, coat well, cover and marinate for 24 hours.
The next day, in a large saucepan over medium-high heat, add oil. When hot, working in batches, add chicken pieces and cook until brown, about 5 to 6 minutes or until browned. Transfer to a plate and set aside.
Add ghee and reduce the heat to medium. Add onions and sauté until start to soften, about 3 minutes. Add garlic and ginger; sauté for 1 minute. To this, add garam masala, smoked paprika, cumin, coriander and turmeric; sauté for 30 seconds, coating the onions. Add fire roasted diced tomatoes and tomato paste; reduce the heat if bubbling too much. Stir well before adding brown sugar, cayenne pepper and sea salt; stir and simmer for 10 minutes, stirring occasionally.
Stir in heavy cream and return chicken and its juices to the saucepan. Stir once again and simmer for 10 minutes or until chicken is heated through. Garnish with cilantro and serve with basmati rice and naan bread.