Episode 20

The semi-finals are in full swing, and just six extraordinary cooks are still in the race. But nothing could have prepared them for what's now in store.

The brief in this episode has been set by one of the most revered chefs in the world, a man who needs very little introduction: Heston Blumenthal. Heston is a pioneer in the world of molecular gastronomy, and his three-Michelin-starred restaurant The Fat Duck has inspired generations by ripping up the culinary rulebook. His dishes excite all the senses, giving the diner an experience like no other. This year marks the 30th birthday of his groundbreaking restaurant, and the semi-finalists are honouring the celebration at MasterChef HQ.

The contestants must dig deep, as working in teams, they will be asked to recreate some of Heston's most celebrated dishes. The recipes are detailed and complex, but if they do them right, the results should be out of this world. It's time to roll out the liquid nitrogen as the hopefuls take on recipes that have taken years to develop and master.

After judging their take on his creations, Heston next gets the chance to taste the semi-finalists' own food, as the contenders' next brief is to cook a dish filled with theatre and magic – something truly ambitious that plays with the senses and is full of wonder. Emotion and storytelling are crucial components, and Heston will be hoping for some passion in the plates he tastes.

At the end, five deserving cooks will go through to the next round, leaving one to savour the memories as they head back home. The hunt for this year's champion continues.