In a large Ziplock bag or bowl, combine yogurt, garlic, lemon juice, ginger, garam masala, turmeric, cumin, salt, black pepper, and cayenne. Add chicken and coat well. Refrigerate for at least three hours or overnight.

Heat butter in a large skillet over medium-high heat. Sear marinated chicken pieces in batches until golden brown (2-4 minutes per side). Remove and set aside.

In the same skillet, add tomato sauce, heavy cream, tomato paste, and sugar. Stir to combine and simmer on low heat for about 20 minutes until the sauce thickens.

Return the seared chicken to the skillet and gently fold to coat with sauce. Simmer for an additional few minutes.

Serve garnished with fresh cilantro.