Lamb Tikka Masala

Name: Lamb Tikka Masala
Ingredients: 2 tablespoons garam masala, divided, recipe follows; 2 teaspoons kosher salt, divided; 1/2 teaspoon toasted, ground cumin; 1/2 teaspoon toasted, ground coriander; 1/2 teaspoon freshly ground black pepper; 1 1/2 pounds lamb leg sirloin, trimmed and cut into 1-inch cubes; 1 cup plain whole milk yogurt; 1/4 cup vegetable oil; 1 large onion, chopped; 4 cloves garlic, minced; 1 tablespoon grated fresh ginger; 1 medium serrano chile, seeded and minced; 1 (28-ounce) can diced tomatoes; 1 cup coconut milk; Fresh mint or cilantro leaves; 2 tablespoons cardamom seeds; 2 tablespoons coriander seeds; 1 tablespoon cumin seeds; 1 tablespoon brown mustard seeds; 2 tablespoons black peppercorns; 20 cloves; 1 dried arbol chile stemmed, seeded and crumbled; 1 (2 1/2-inch) cinnamon stick, broken in 1/2; 1 teaspoon freshly grated nutmeg