Step 1: Marinate the Chicken

• In a large bowl, combine Greek yogurt, lemon juice, ginger-garlic paste, turmeric, garam masala, cumin, coriander, smoked paprika, chili powder, salt, and oil. Mix well.
• Cut the chicken into bite-sized chunks and coat them thoroughly in the marinade.
• Cover and refrigerate for at least 1 hour (preferably overnight for maximum flavor).

Step 2: Cook the Chicken

• Heat a grill pan, skillet, or broiler over medium-high heat.
• Drizzle a little oil on the pan and sear the marinated chicken for about 4-5 minutes on each side until slightly charred and cooked through. (Alternatively, bake at 400°F for 15-20 minutes).
• Set aside while preparing the sauce.

Step 3: Prepare the Masala Sauce

• In a deep skillet or saucepan, heat butter and oil over medium heat.
• Add chopped onions and sauté until golden brown (about 5-7 minutes).
• Stir in garlic and ginger, cooking for another minute until fragrant.
• Add cumin, coriander, garam masala, turmeric, smoked paprika, and chili powder. Stir for 30 seconds to toast the spices.
• Mix in tomato paste and cook for 2 minutes, then pour in the crushed tomatoes.
• Simmer for 10 minutes, stirring occasionally, until the sauce thickens.
• Reduce heat and slowly stir in heavy cream. Add sugar (if using) and season with salt and pepper to taste.

Step 4: Combine and Serve

• Add the grilled chicken pieces to the sauce, stirring to coat evenly.
• Simmer for 5 more minutes to let the flavors meld.
• Stir in lemon juice and garnish with fresh cilantro.
• Serve hot with basmati rice, naan, or roti.