In the last quarter-final, the four best chefs from this week's heats come together to compete in two challenges set by judges Anna Haugh and Marcus Wareing. To earn the last two places in the semi-finals, the chefs must show off their creativity in an invention test, then prepare food for some of the UK's most hard to please food critics. Only the most exciting culinary talents will continue in the competition.

In the first challenge, the judges set a pastry Invention test with a twist: the dessert must be based on a savoury ingredient. Next to the classic pastry ingredients in the larder, the chefs have cheeses, bacon, vegetables, chillies and herbs to build their dishes around.

Then, the chefs face one of the toughest rounds of the competition. In just one hour and fifteen minutes, they must serve up an exceptional two-course meal to three of the country's biggest restaurant critics. This is their chance to shine as they cook for people who could one day make or break their careers.

The semi-finals continue with only the eight best chefs left standing. They are now split into two groups and over the next two nights will strive to secure an all-important place in Finals Week.

Tonight, the first four face two challenges, beginning with their first task outside the MasterChef kitchen. The MasterChef: The Professionals pop-up opens its doors in a warehouse microbrewery in industrial east London.

In recent years, pop-up restaurants have revolutionised the way we eat. With a vibrant mix of cuisines on offer in dynamic settings, some of the most exciting food currently in the UK has come from the pop-up industry, enabling creative chefs to make a name for themselves without the costs of opening a traditional restaurant.

The semi-finalists have an opportunity to make an impression in this vibrant world as they cook their own dish for 20 of the UK's top pop-up chefs and entrepreneurs. They each have three hours to deliver a dish designed to get this influential crowd talking, but with makeshift workstations, limited equipment and no ovens, who will be able to adapt their fine-dining style and serve up a dish that says star quality?

For the second task, the four chefs return to the MasterChef kitchen and have one hour and 45 minutes to cook their own Desert Island Dish – a dish they would take with them if they were stranded on a desert island. With places in Finals Week at stake, the slightest mistake could mean they miss out on the chance of a lifetime.

Once Marcus, Anna and Gregg have tasted all the dishes, it will be end of the road for one chef, while the best three go through to Finals Week and stay in the running for the MasterChef: The Professionals 2022 title.