Chicken Tikka Masala

INGREDIENTS

• 1 1/2 pounds boneless, skinless chicken breasts (3 to 4 breast halves total)
• 1/4 cup plain whole-milk Greek-style yogurt
• 2 tablespoons peanut oil
• 2 teaspoons fresh lime or lemon juice
• 1 large clove garlic, minced
• 1 tablespoon ground coriander
• 1 1/2 teaspoons ground cumin
• 1/2 teaspoon ground cardamom
• 1/2 teaspoon ground nutmeg
• 1 1/2 teaspoons paprika
• 1/2 teaspoon cayenne
• 1 tablespoon grated peeled fresh ginger (from 1-inch piece)
• 4 tablespoons (1/2 stick) unsalted butter
• 1 large white onion, finely chopped
• 1 1/2 cups canned tomato purée (see Cook's Notes for a fresh-tomato alternative)
• 3/4 cup water
• 1/2 cup heavy cream or half-and-half
• 1 1/4 teaspoons kosher salt
• 1/2 teaspoon freshly ground black pepper
• 1/2 cup chopped fresh cilantro plus additional sprigs for garnish
• Naan (Indian flatbread) and/or cooked
• Meat mallet or rolling pin, Microplane