After flying in from Perth last week, Greta, 12, led some cooking classes at the Wonderful Worlds of Whampoa. Tasmania boy Jack, 15, ventured to Stanley for a friendly cook-off with another Junior Masterchef from Finland.
The young chefs wowed Australian TV viewers with their extraordinary cooking skills: Greta perfected a delicate, Japanese-inspired scampi dish in the final, while Jack's complex snail porridge - a signature dish of Britain's most acclaimed gastronomy chef Heston Blumenthal - sent him straight to the last round.
Although they both fell in love with cooking in their homeland, their specialities vary significantly in style.
"I love French food. It's sort of my style," Jack says. "I love cheese."
After the competition ended, Jack tagged along with his dad on a business trip to France. There, he found himself in cheese and butter heaven at a local market next to the hotel.
Spanish, too, is very much Jack's idea of good food. "I like the whole tapas idea," he says.
Tapas come in small portions, so diners can share an array of dishes, instead of sticking to what's on their own plate as is the case in most Western cuisines.
Greta, meanwhile, has a keen palate for Asian flavours, especially Vietnamese food. "I really like Vietnamese because of all the flavours. There is a lot of mint, coriander, lemongrass ... " she says. "It's really fresh as well. And a lot of it is quite simple."
But the 12-year-old loves to explore lots of different cuisines, and she tends to cook the iconic cuisine of whichever country she has recently visited. And she was evidently impressed by her food quest to Hong Kong, "I'm sure my family will be getting a lot of Chinese food after this trip," she giggles.
But she is likely to switch back to making pho, Vietnam's famed noodles, and spring rolls because she'll be visiting Vietnam next April, as her birthday present. "I'm lucky to have the chance to be there so that I can taste different food and do some cooking courses," she says.
So with Christmas approaching, what will the two young chefs be serving up on their festive tables?
"I'm making a Christmas pudding with a candied clementine in the middle, like a mandarin," Jack says. The delicious dessert features in a cookbook by Blumenthal, his favourite chef.
"Christmas in Australia is usually very hot," Jack adds. "We usually have barbecue [food], like a roast turkey and roast pig."
Last Christmas, the Larks made Chinese-style barbecued pork, taking the advice of Hong Kong's famous food critic Suzi Wong, who visited Hobart last year and invited Jack to cook her a four-course meal.
Every year, Greta celebrates Christmas at her grandparents' house. While they cook the main course - including a big roast turkey, peaches with jam, and lots and lots of veggies - "I do the nibblies and the entrees," she says.
This year, Greta's menu will include most of the dishes she made for the Masterchef's Christmas challenge. "There will be oysters with Asian flavours, and scallops with a pear puree and caviar," she adds.
One very special dish is the mushroom tarts Greta dedicates to her mum, who misses out on most of the traditional food because she's vegetarian. She'll also make prawns for her dad as they're his favourite.
To top off a thoroughly satisfying Christmas menu, Greta will make a plum pudding to be drenched with her grandma's delicious brandy custard.
"This year, I don't think I'll be able to get in the car after eating all that," Greta jokes.
See Greta trying dim sum with our junior reporters in the video below