Marinate the Chicken: In a mixing bowl, combine the chicken thighs with salt, garlic powder, sweet paprika, curry powder, and Greek yogurt. Cover with plastic wrap and let it marinate for at least 15 minutes.

Cook the Chicken: Heat a large skillet over medium-high heat and add vegetable oil. Add the marinated chicken in a single layer and sauté for 8-10 minutes until golden brown, then remove from skillet.

Sauté the Aromatics: In the same skillet, lower heat to medium and add butter. Once melted, add minced garlic and diced onion; sauté for 4-5 minutes until the onion is translucent.

Build the Sauce: Pour in the tomato sauce and sprinkle sugar. Stir well and simmer for about 2-3 minutes, then mix in the cooked chicken.

Add the Cream: Slowly pour in heavy cream while stirring to create a smooth sauce. Cook for another 2-3 minutes on low heat.

Season the Sauce: Add cayenne pepper, garam masala, and black pepper. Simmer on low heat for about 10 minutes to allow flavors to meld.

Finish with Butter: Stir in any remaining butter until melted and fully incorporated. Adjust seasoning as needed.

Serve and Enjoy: Serve hot with naan and rice to soak up the sauce.