Meatballs in cardamom sauce

Name: Meatballs in cardamom sauce
Cuisine: Southern, American, Moroccan, African
Ingredients: 1kg / 2¼l boneless lamb, cut into 5-cm / 2-inch pieces; 125g / 4oz (/2 cup) ghee, plus extra for meatballs pinch of ground ginger pinch of salt; 3 black cardamom pods, ground; 1.2 litres / 2 pints (5 cups) natural (plain) yoghurt; 1 litre / 1% pints (4¼ cups) lamb stock (see page 636); 4 black cardamom pods; 8 green cardamom pods; 6 cloves; 3 teaspoons ground fennel; 3 teaspoons ground ginger; 3 garlic; 1 tablespoon Fried Onion Paste (see page 57) see recipe; ½ teaspoon dried mint leaves