Step 1: In a large bowl, combine chicken pieces with Greek yogurt, 1 tbsp ginger-garlic paste, turmeric powder, red chili powder, 1 tsp garam masala, and 1/2 tsp salt. Mix well to ensure all chicken is coated. Cover and refrigerate for at least 30 minutes, or preferably 2-4 hours, or even overnight.
Step 2: Heat 1 tbsp olive oil and 1 tbsp butter in a large heavy-bottomed pan or Dutch oven over medium-high heat. Add the marinated chicken in a single layer, ensuring not to overcrowd the pan. Sear the chicken for 3-4 minutes per side until lightly browned. Remove the chicken from the pan and set aside.
Step 3: Reduce heat to medium. Add the remaining 1 tbsp butter to the pan. Add the finely chopped onion and cook until softened and translucent, about 5-7 minutes. Add the remaining 1 tbsp ginger-garlic paste and cook for another minute until fragrant.
Step 4: Stir in the cumin powder, coriander powder, and crushed kasuri methi. Cook for 30 seconds, stirring constantly, until aromatic. Be careful not to burn the spices.
Step 5: Pour in the crushed tomatoes and chicken broth (or water). Bring the mixture to a simmer, then reduce heat to low, cover, and let it cook for 15-20 minutes, stirring occasionally, until the sauce has thickened and the flavors have melded.
Step 6: Remove the pan from heat. Carefully transfer the sauce to a blender and blend until completely smooth. If you prefer an extra silky sauce, pass it through a fine-mesh sieve back into the pan.
Step 7: Return the pan with the smooth sauce to medium-low heat. Stir in the seared chicken pieces. Add the heavy cream and sugar (if using). Gently simmer for another 5-7 minutes, allowing the chicken to cook through and absorb the flavors of the sauce. Adjust salt to taste.
Step 8: Garnish generously with fresh chopped cilantro before serving. Serve hot with basmati rice and warm naan bread. Enjoy your homemade Butter Chicken Recipe!