1. In a large bowl, combine the yogurt, lemon juice, garam masala, turmeric, chili powder, cumin, and salt. Add the chicken pieces and mix well to coat evenly. Cover and marinate in the fridge for at least 30 minutes, or up to 4 hours if you have the time.
2. Heat 2 tablespoons of butter in a large skillet over medium heat. Add the chopped onion and cook, stirring occasionally, until soft and golden, about 8-10 minutes. This step brings out a sweetness that balances the spices—don’t rush it!
3. Add the minced garlic and grated ginger to the pan and cook for another minute until fragrant.
4. Stir in the crushed tomatoes and cook for 10 minutes, letting the sauce thicken and flavors meld. Stir occasionally to prevent sticking.
5. While the sauce simmers, heat a separate skillet or grill pan over medium-high heat. Add the marinated chicken (shaking off excess marinade) and cook until browned on all sides, about 5-6 minutes. You don’t need to cook it through, as it will finish in the sauce.
6. Transfer the browned chicken into the tomato sauce. Add the remaining 1 tablespoon of butter and pour in the heavy cream and water or chicken broth. Stir everything together gently.
7. Simmer on low heat for 15-20 minutes, uncovered, until the chicken is fully cooked and tender, and the sauce is thick and creamy. If the sauce gets too thick, add a splash more water or broth.
8. Give the dish a taste and adjust salt or chili powder to your preference.
9. Garnish with fresh cilantro leaves just before serving.

From my experience, marinating the chicken isn’t about the minimum time—it’s about what your schedule allows. On hectic nights, even 30 minutes makes a difference in flavor and tenderness.