In a large nonstick frying pan over medium heat, heat the oil and butter together until butter is melted. Add the chicken, onion, garlic, ginger, and chile. Saute, about 7 minutes until the chicken is mostly cooked and the onion has gone clear.
Stir in the tomatoes, tomato sauce, garam masala, and curry powder. Reduce the heat and simmer for 10 minutes. Stir in the cream, if using, and heat for another five minutes or so. Garnish with the cilantro and serve.
Remember: If you're making this for the Whole 30, you'll need to use ghee instead of butter, and omit the cream.
Nutritional values are approximate and are based on 1/4 of the recipe and do include the optional cream. Refrigerate leftovers promptly and use within 4 days.