Tamara Graffen

A mystery box of Thai ingredients and only 75 minutes to cook has contestants stumped, as they try to gain a huge advantage for the upcoming invention test.

The top six contestants do their best in a mystery box challenge in order to demonstrate their progress in the competition.

Contestants from the blue team face an elimination round as they put their tastebuds to the test. In the second round, contestants must make an impressive dish in just 75 minutes to keep their spot in the competition.

The bottom three contestants must create a dish that will secure them a spot in the semifinal. The judges take part in a masterclass run by Shannon Bennett with the contestants. Curtis Stone appears for an invention test relay.

The contestants participate in a relay challenge after they are split into teams of four. Challengers each have 15 minutes to cook, and just 45 seconds to pass their dish on to their team-mate.

The top four contestants go to Melbourne restaurant, Dinner By Heston, to take part in a service challenge.