Season chicken lightly with salt.
Heat butter in a large skillet over medium-high heat.
Cook chicken until browned on the outside, then remove temporarily.
Add onion and cook until softened.
Stir in garlic, ginger, garam masala, paprika, cumin, turmeric, and chili powder.
Cook briefly until fragrant.
Add tomato sauce and simmer for several minutes.
Stir in heavy cream and return chicken to the skillet.
Simmer until chicken is fully cooked and sauce thickens slightly.
Garnish with cilantro and serve hot