Week four of the heats has arrived, and 12 fresh-faced contenders are pinning their hopes on winning a MasterChef apron - their ticket to progress in the competition. Only the best on the day will make it into this week's quarter-final and still be in the running for the title.

Four sparkling MasterChef aprons are on offer, as John and Gregg ask the first six contenders to transform a chosen everyday ingredient from Basic To Brilliant. There have been some ingenious plates delivered so far, so the bar is extremely high. Restaurant-quality dishes will be expected from the hopefuls, who include a doctor, a lawyer and an actor. This is the first time the judges will sample their cooking, so they will be hoping for plates that sing with personality. It's straight through for the two strongest as they try their MasterChef aprons on for size.

The stakes are high for the remaining cooks, who need to come back fighting as there are only two more aprons up for grabs. To win one, they will need to think on their feet and produce a stunning dish featuring prawns. The bountiful larder is there for the odd flourish, and they will have just 45 minutes to show John and Gregg what they are made of. The two who manage to make their prawns pop will don the prized remaining MasterChef aprons.

The action-packed episode ends with the true test of endurance. The four best cooks must prepare an exquisite two-course menu for three diners who have all faced this pressure head-on: 2007 MasterChef champion Steven Wallis, 2021 finalist Alexina Anatole, and 2006 finalist Dean Edwards. They, along with the judges, will be anticipating food that hits high standard and leaves them wanting more. So the average dinner-party dish will not be enough, and the cooks must pull out all the stops to impress.

All four will be hoping to hear their name announced as a quarter-finalist, but two will be sorely disappointed as their dream of becoming the next MasterChef champion will be over.

It's quarter-final time, as this week's six best cooks don their well-earned MasterChef aprons ready to bring their A-game. A place in Knockout Week is now within touching distance, but any slip-ups might cost them the competition.

John and Gregg have invited a special guest to set the brief – one of the country's most exciting culinary stars, April Jackson. They will have 90 minutes to deliver a dish that celebrates cheese. April loves everything about cheese, but she wants something that will truly linger in the memory. Every cheese offers its own strength and taste, so this really is a test that will get the amateurs' creative juices flowing. After a total cheese-fest, it's down to the judges to pick their favourites.

There's only room in Knockout Week for three, and the lucky ones that make it will be well on the way to MasterChef stardom.