Pakistani Slow-Cooked Lamb Stew (Dumbay ki Nihari)

Ingredients

• 2 tbsp. poppy seeds
• 1 tbsp. coriander seeds
• 1 tsp. cumin seeds
• 1 tsp. fennel seeds
• 1⁄2 tsp. whole black peppercorns
• 1⁄4 tsp. freshly grated nutmeg
• 5 whole cloves
• 3 green cardamom pods
• 1 black cardamom pod
• 1 whole star anise
• 1 stick cinnamon, halved
• 1 cup canola oil
• 1 medium yellow onion, very thinly sliced
• 3 lamb shanks, halved crosswise
• 1 tbsp. cayenne
• 2 cloves garlic, mashed into a paste
• 1 (3") piece of ginger, peeled (1" mashed into a paste, 2" julienned, for serving)
• 1⁄4 cup flour
• 2 tbsp. ghee, melted
• Chopped cilantro, lemon or lime wedges, minced Thai chiles, and naan bread, for serving (optional)
• Kosher salt, to taste