Lamb Tikka Masala - Alton Brown

Ingredients

• 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 half
• 1 teaspoon freshly grated nutmeg
• 2 tablespoons garam masala, divided
• 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