Easy Butter Chicken

Bahan-bahan (4 porsi)

• 1½ lbs chicken tenderloins, (tendons trimmed, or boneless skinless breasts, cut into 1½-inch (4-cm) pieces (see note))
• 1¼ teaspoons salt
• 2 teaspoons garam masala
• 3 tablespoons all-purpose flour
• 2 tablespoons unsalted butter
• 1 tablespoon vegetable oil
• 1 medium yellow onion, (finely chopped (about 1 cup))
• 1½ tablespoons finely chopped fresh ginger, (from a 2-inch (5-cm) knob )
• 1 teaspoon ground coriander
• 1¾ teaspoons ground cumin
• ⅛ teaspoon cayenne pepper ((optional))
• 1 (8-oz) can tomato sauce
• 1 cup heavy cream
• ¾ teaspoon sugar
• ¼ teaspoon freshly ground black pepper
• 3 tablespoons water
• 3 tablespoons chopped fresh cilantro ((optional))
• Basmati rice
• Mango chutney, (such as Major Grey's)