The heat is on. A fresh group of home cooks from around the country will eagerly tackle challenges that will see one of them take home the title and $250,000.

After a record-breaking first-round cook that saw an extraordinary 20 aprons handed out, only four aprons remain. Who will have what it takes to impress the judges?

Top 24 Mystery Box Challenge: Elena Duggan The top 24 contestants enter the kitchen for their first mystery box challenge.

The contestants gather at Gradi, one of Melbourne's leading Italian restaurants before being split into two teams who must prepare four dishes for 250 hungry diners to avoid the elimination challenge.

The three best performers from the invention test are now vying for a chance at immunity. Does the amateur cook have what it takes to out-cook the professional?

The contestants are split into teams of four in a relay challenge as each member has 15 minutes to cook and only 45 seconds to hand over to the next cook in the relay.

The three contestants with the least impressive dishes from the invention test face off in the pressure test. To survive they must keep up with Gary Mehigan as he prepares his classic roast chicken.

The losing team from the Italian service challenge face elimination. Who will be the next to leave the competition? Plus, don't miss the first MasterClass of 2017 led by judges Gary, George and Matt.

Hidden Pairs Elimination Challenge Bottom 4 cooking of in the mystery pairs elimination challenge.

The bottom three contestants from the invention test now face a pressure test to recreate Andy Bowdy's Rita cake to avoid elimination. Who will be the next to leave the competition?

The losing team from the relay challenge now face elimination and the contestants have 90 minutes which they can use to buy ingredients. Who will be the next to leave the competition?

In the third and final round of the judge's auditions, six contestants are vying for the final apron, which will secure them a place in the top 24.

Each judge has placed three of their favourite ingredients into the mystery box and contestants will have 75 minutes to create a remarkable dish for a chance at immunity.

The top three contestants from the invention test now compete in creating a family meal for four in half-an-hour. The winner will then take on a professional chef for a chance at immunity.

Contestants have an hour to create a delicious dish from ingredients found in the Mystery Box set by international celebrity chef Curtis Stone.

Contestants have 90 minutes to create a delicious dessert from the mystery box ingredients. However, only five dishes will be tasted and only three will move on to the immunity challenge.

The bottom four contestants from the invention test must now cook off in the Pressure Test set by one of the world's top chocolatiers to avoid elimination. Who will be next to leave the competition?

Contestants have 75 minutes to create a dish using ingredients from the mystery box with the winner gaining the advantage in the invention test.

Eight contestants now face elimination and must survive three rounds if they are to keep their food dream alive. Will one of the top contenders fail to impress the judges?

The three best-performing contestants from the invention test compete for immunity. Each contestant has 90 minutes to create a dessert while the professional chefs will only have 75 minutes.

Twelve of the previously eliminated contestants now have a chance to cook their way back into the competition. Which one of the home cooks will secure themselves a second chance?

It's Heston Blumenthal week. Heston takes the top 12 contestants on a road trip through regional Victoria; the first stop is the mighty Murray River in Swan Hill.

Contestants split into pairs have 75 minutes to cook one main and one dessert that must incorporate the element of earth. The least impressive team will then need to cook off to avoid elimination.

Contestants have an hour to create a dish from the Mystery Box ingredients, with only three dishes to be tasted. The maker of the winning dish will receive an advantage in the invention test.

MasterChef Australia2016 runner-up Matt Sinclair is on hand to mentor contestants in a pop-up restaurant team challenge to create a three-course menu for 100 diners.