MasterChef Australia's Ben, Sashi and Khanh, must cook for 60 past contestants to make their way into the grand final.
With an open pantry and the garden to use, the top three have to make a main and dessert for 20 alumni each.
Ben, Sashi and Khanh will have four hours to prep before service starts, with the least impressive cook being sent home, leaving the final two to compete in Tuesday night's grand finale.
The MasterChef Australia grand finale will see the top two recreate a challenging dish designed by Heston Blumenthal.
"Well, I can’t give too much away, but safe to say I’ve come up with something very challenging," he told WHO.