Marinate the chicken:
In a large bowl, combine yogurt, lemon juice, cumin, coriander, paprika, turmeric, garam masala, chili powder, garlic, ginger, and salt. Add the chicken pieces and mix until they are fully coated. Cover and refrigerate for at least 1 hour (or overnight for best results).

Cook the chicken:
Preheat your oven to 400°F (200°C) or heat a grill pan over medium-high heat. Thread the marinated chicken onto skewers (or cook directly in a pan) and bake or grill for 10-12 minutes, or until the chicken is cooked through and slightly charred. You can also cook the chicken in batches in a hot skillet if you don’t have skewers.

Prepare the sauce:
While the chicken is cooking, heat oil or ghee in a large pan over medium heat. Add chopped onions and sauté for 4-5 minutes, until softened and golden brown. Add the garlic and ginger and cook for another minute until fragrant.

Simmer the sauce:
Add the crushed tomatoes, cumin, coriander, paprika, garam masala, turmeric, and chili powder (if using). Stir to combine and simmer for 10 minutes, allowing the flavors to meld together.

Combine chicken with sauce:
Once the chicken is cooked, add it to the sauce and stir. Pour in the cream (or coconut milk) and simmer for another 5 minutes until the sauce thickens and the chicken absorbs the flavors.

Serve:
Garnish with fresh cilantro and serve hot with basmati rice, naan bread, or a side of vegetables.