Marinate the Chicken: In a large bowl, combine the chicken pieces with salt, red chili powder, and garam masala. Mix well and let marinate for at least 15 minutes to absorb all the spices., Cooking the Chicken: Heat 2 tablespoons of vegetable oil in a large skillet over medium heat. Once the oil is hot, add the marinated chicken and cook until browned and cooked through, about 5-7 minutes. Remove the chicken from the skillet and set aside., Sauté the Aromatics: In the same skillet used for the chicken, melt 4 tablespoons of butter over medium heat. Add the chopped onion and sauté until translucent, about 5 minutes., Add Garlic and Ginger: Stir in the minced garlic and ginger, cooking for an additional 1-2 minutes until fragrant., Incorporate Tomatoes: Pour in the crushed tomatoes. Stir well to combine, and let the mixture simmer for about 5 minutes. This will allow the tomatoes to break down and create a rich base for the sauce., Creamy Finish: Reduce the heat to low and stir in the heavy cream, sugar, garam masala, and salt. Allow this to cook on low heat for another 5-7 minutes. The sauce should begin thickening and becoming creamy., Adjust the Seasoning: Taste the sauce and adjust salt and spices as necessary, adding more red chili powder for heat if desired., Return the Chicken: Once the sauce is creamy and well-seasoned, add the cooked chicken back to the skillet. Stir gently to coat the chicken with the sauce., Simmer Together: Let the chicken simmer in the sauce for an additional 5 minutes, allowing the flavors to meld beautifully.