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. Created in the 1970s and still a restaurant favourite, they will need a steady hand and a cool head to deliver a perfect version of confi'd salmon with sauteed bayonne ham and a piperade of tomatoes and green pepper for the chef himself to taste. But the chefs' work is not yet done. Next the semi-finalists return to the MasterChef kitchen to battle it out for just one place in the final week. They have two hours to cook a perfect main course and dessert inspired by their time away for Monica and Marcus, anything less could cost them their place in the competition. The pressure is on to step up to the mark and show the judges why they deserve to go on in this the competition.