Mix 1 cup of plain yogurt, 1 tablespoon of minced garlic, 1/2 tablespoon of grated ginger, and 1 tablespoon of garam masala in a large bowl. Add the chicken thighs and toss to coat. Cover and marinate in the refrigerator for at least 30 minutes.
Heat a splash of oil in a large skillet over medium-high heat. Add the marinated chicken pieces and sear for 5 to 6 minutes until browned and slightly charred on the edges. Remove the chicken from the skillet and set aside.
In the same skillet, reduce heat to medium and add the remaining 1 tablespoon of minced garlic and 1/2 tablespoon of grated ginger. Sauté for 1 minute until fragrant.
Stir in the remaining 1 tablespoon of garam masala and pour in the 28 oz of crushed tomatoes. Bring to a gentle boil, then reduce heat and simmer for 15 minutes.
Stir the 1/2 cup of heavy cream into the tomato sauce. Add the browned chicken back into the skillet. Simmer for an additional 10 minutes until the chicken is cooked through.
Garnish with 1/4 cup of chopped fresh cilantro. Serve hot with 2 cups of cooked basmati rice, 4 pieces of warmed naan bread, and extra plain yogurt for dipping.