In a large skillet, heat the vegetable oil over medium heat. Add the chopped onion and sauté until translucent, about 5 minutes.
Stir in the minced garlic and grated ginger, cooking for an additional 1-2 minutes until fragrant.
Add the chicken pieces to the skillet and cook until they are browned on all sides, about 5-7 minutes.
Sprinkle the garam masala, cumin, coriander, turmeric, and chili powder over the chicken. Stir well to coat the chicken in the spices.
Pour in the crushed tomatoes and stir to combine. Bring the mixture to a simmer and cook for 10 minutes, allowing the flavors to meld.
Reduce the heat to low and stir in the heavy cream and sugar. Simmer for another 5 minutes, stirring occasionally. Season with salt to taste.
Serve hot, garnished with chopped cilantro over rice or with naan bread.