It's the semi-finals. First up, the chefs head to London's Knightsbridge to cook for the formidable French chef Pierre Koffmann. With a fearsome reputation and over 50 years of experience, he has trained a generation of great chefs, including Gordon Ramsay, Michel Roux Jr and Tom Kitchen. The semi-finalists face the daunting task of a lunchtime service under this culinary superstar. Each is responsible for a Koffmann classic from the lunch menu, and they must immediately get to grips with his back-to-basics, instinctive approach to cooking. And if that wasn't intimidating enough, after service they must each cook Pierre one of his own famous signature dishes.