Cut chicken into bite-sized pieces. In a bowl, mix yogurt with garlic, ginger, cumin, coriander, garam masala, and salt. Coat the chicken in the mixture and let it marinate for at least 30 minutes.

Heat butter in a large skillet over medium heat. Add marinated chicken and cook until golden brown on all sides (about 10 minutes). Remove from skillet and set aside.

In the same skillet, add more butter if needed and sauté chopped onions until translucent. Stir in tomato puree and spices; cook for about 5 minutes.

Return chicken to skillet and stir well to coat in sauce. Gradually add heavy cream while mixing; simmer for another 10-15 minutes.

Taste and adjust seasoning as needed. Serve hot with naan or rice.