1. In a saucepan, melt 2 tablespoons of butter. Add the leeks and cook, stirring, for 8 minutes.2. Add the cream and reduce by a third.3. In a bowl, mix the minced lamb, coriander, cumin, breadcrumbs, and egg. Season with salt and pepper.4. Mix the lamb by hand and form balls of equal size.5. In a saucepan, melt the remaining butter. Add the balls and cook until browned on all sides, over high heat. Reduce heat and cook for 8 minutes.6. Serve the balls on a bed of leeks.