Marinate the Chicken:
Combine yogurt, lemon juice, turmeric, cumin, coriander, paprika, and salt in a bowl. Add chicken pieces and toss to coat thoroughly. Cover and refrigerate for at least 1 hour or overnight.Brown the Chicken:
Heat 1 tbsp vegetable oil in a large pan over medium heat. Brown the marinated chicken on all sides. Remove chicken from the pan and set aside.Sauté Onion and Aromatics:
Add the remaining 1/2 tbsp oil to the same pan. Sauté the finely chopped onion until golden. Stir in minced garlic and ginger; cook for 2 minutes.Simmer Tomato Sauce:
Pour in the tomato sauce. Simmer for about 10 minutes, stirring occasionally. If using, add fenugreek leaves during this step.Combine Chicken with Cream:
Return the cooked chicken to the pan. Mix well to coat with the sauce. Pour in the heavy cream and add the butter. Stir until the butter melts and the sauce becomes creamy.Finish with Garam Masala:
Simmer for an additional 5 minutes. Sprinkle garam masala over the chicken and stir. Garnish with fresh cilantro before serving. Serve over warm Basmati rice.