Whisk the yogurt with the lemon juice, turmeric, garam masala and cumin in a medium bowl. Add the chicken, toss to coat everything well, and refrigerate for 2 hours, or up to one day.
Heat the butter and oil over medium high heat and add the onion; cook, stirring frequently, for 3 minutes. Add the garlic and ginger and cook, stirring frequently, for another minute. Add the cinnamon stick, tomatoes, jalapeño and salt and cook until the tomatoes start to break down, about 5 minutes, stirring occasionally.
Add the chicken to the pan and cook for 2 minutes on each side, then add the stock, bring to a boil, reduce to simmer, and cook uncovered for 20 minutes.
Whisk the cream and tomato paste together and add to the chicken, stirring to combine. Cook uncovered for 10 more minutes.
Serve over fragrant rice and garnish with cilantro leaves if desired.
Recipe by Cooking With Michele® at https://cookingwithmichele.com/2021/04/butter-chicken/