For the Chicken Marinade:

• 2 large boneless, skinless chicken breasts (or 4 chicken thighs)
• 1 cup Greek yogurt
• 1 tablespoon lemon juice
• 1 tablespoon ginger-garlic paste
• 1 teaspoon turmeric powder
• 1 teaspoon garam masala
• 1 teaspoon ground cumin
• 1 teaspoon ground coriander
• 1 teaspoon smoked paprika
• ½ teaspoon chili powder
• 1 teaspoon salt
• 1 tablespoon oil

For the Masala Sauce:

• 2 tablespoons butter or ghee
• 1 tablespoon oil
• 1 large onion, finely chopped
• 2 cloves garlic, minced
• 1-inch ginger, grated
• 1 teaspoon cumin
• 1 teaspoon coriander
• 1 teaspoon garam masala
• ½ teaspoon turmeric
• ½ teaspoon smoked paprika
• 1 teaspoon chili powder
• 2 tablespoons tomato paste
• 1 can (14oz) crushed tomatoes
• 1 cup heavy cream (or coconut milk)
• 1 teaspoon sugar (optional)
• Salt & pepper, to taste
• 1 tablespoon lemon juice
• ¼ cup chopped cilantro (for garnish)