In a large mixing bowl, combine the ground chicken, egg, and breadcrumbs along with garam masala, cumin, coriander, salt, and pepper. Mix thoroughly using your hands or a spatula until everything is well incorporated. Shape the mixture into golf ball-sized meatballs.

Heat a large pot or skillet over medium heat and add a splash of oil. Once hot, carefully place the meatballs in the pot, cooking for about 5–7 minutes until browned on all sides. Remove and set aside.

In the same pot, pour in the plain tomato sauce, scraping up any browned bits. Add the remaining spices and stir well. Bring to a gentle simmer over low-medium heat for about 2–3 minutes.

Use an immersion blender to blend the sauce until smooth. Alternatively, transfer the sauce to a standard blender, blend until creamy, and return to the pot.

Return the browned meatballs to the pot, gently coating them in the tomato gravy. Allow to simmer for about 5 minutes on low heat.

Stir in the cream and butter, cooking on low heat for another 2-3 minutes until heated thoroughly.