In a large bowl, mix the chicken with salt, paprika, garam masala, turmeric, chili powder, black pepper, and Greek yogurt. Let it marinate for at least 15 minutes.
Melt the butter with olive oil in a large skillet over medium heat.
Add the chopped onion and sauté until golden brown, about 5 minutes.
Stir in the ginger garlic paste and cook for 1-2 minutes until fragrant.
Add the marinated chicken and cook until no longer pink, about 6-8 minutes.
Pour in the tomato sauce and sugar. Stir well and simmer for 10 minutes.
Stir in the heavy cream and let it simmer for another 5 minutes until the sauce thickens.
Garnish with fresh cilantro and serve hot with rice or naan.