In a bowl, combine chicken pieces with yogurt, 1 tbsp ginger garlic paste, 1 tsp garam masala, 0.5 tsp turmeric, 0.5 tsp chili powder, and 0.5 tsp salt. Mix well and let marinate for at least 15 minutes (or up to 4 hours in the fridge).

Heat 1 tbsp ghee or butter in a large skillet or Dutch oven over medium-high heat. Add the marinated chicken in a single layer (you may need to do this in batches) and sear for 2-3 minutes per side until lightly browned. Remove chicken and set aside.

Reduce heat to medium, add the remaining 1 tbsp ghee or butter. Add the 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.

Stir in 1 tsp garam masala, 1 tsp cumin powder, 1 tsp coriander powder, 0.5 tsp turmeric powder, and 0.5 tsp red chili powder. Cook for 1 minute, stirring constantly, until aromatic.

Pour in the crushed tomatoes and chicken broth. Bring to a simmer, then reduce heat to low, cover, and cook for 10-15 minutes, allowing the flavors to meld.

Stir in the heavy cream and sugar (if using). Return the seared chicken to the skillet, stirring to coat. Simmer gently for another 5-10 minutes, or until the chicken is cooked through and the sauce has thickened slightly. Season with salt and pepper to taste.

Garnish generously with fresh chopped cilantro and serve hot with basmati rice and warm naan bread.