Instructions:

1. Marinate the Chicken

   In a bowl, mix the yogurt, lemon juice, turmeric, garam masala, cumin, chili powder, garlic, ginger, and salt. Add the chicken pieces and coat them thoroughly with the marinade. Cover and refrigerate for at least 1 hour, preferably longer (up to overnight).

2. Cook the Chicken

   Preheat your oven to 400°F (200°C). Place the marinated chicken pieces on a baking sheet lined with foil. Bake in the oven for about 20-25 minutes, or until the chicken is cooked through and starting to brown on the edges.

3. Make the Sauce

   While the chicken is baking, melt butter in a large pan over medium heat. Add the chopped onions, garlic, and ginger. Sauté until the onions are soft and golden. Add the tomato puree, chili powder, garam masala, cumin, and turmeric. Cook for about 5-7 minutes, or until the sauce thickens and darkens in color. Once the sauce is cooked, blend it until smooth using an immersion blender or in a regular blender (be careful of hot splashes).

4. Combine Chicken and Sauce

   Return the blended sauce to the pan, add the baked chicken pieces, and stir well. Add the heavy cream and simmer for another 5-10 minutes. Taste and adjust seasoning with salt and a little sugar if needed.

5. Garnish

   Garnish with chopped cilantro before serving.

6. Serve

   Serve the butter chicken hot with steamed rice, naan, or flatbreads.