In a bowl, combine the chicken pieces with yogurt, garam masala, turmeric, cumin, salt, and lemon juice. Mix well and let it marinate for at least 30 minutes.

In a large skillet, melt the butter over medium heat. Add the chopped onion and sauté until golden brown.

Stir in the minced garlic and grated ginger, cooking for an additional minute until fragrant.

Add the marinated chicken to the skillet and cook until browned and cooked through, about 8-10 minutes.

Pour in the crushed tomatoes and stir well. Let it simmer for 10 minutes.

Reduce the heat and stir in the heavy cream, sugar, ground coriander, and chili powder. Cook for another 5 minutes, stirring occasionally.

Adjust seasoning if necessary.

Garnish with fresh cilantro and serve hot with rice or naan.