"I have always aspired to present something made entirely out of meat -- so I gave it a go."
Last year's experiment did not come without its challenges, such as keeping it light and ensuring there was no odour to the meat.
"I was fortunate enough to have access to a cool store -- the base took a few months to make -- but the Friday before, I spent all day stapling meat on. I kept running out and had to go back to the butcher."
This time she's calmer and more relaxed with the whole process, but when working with something as unpredictable as food nothing is completely certain.
Designers have to appreciate the delicacies of working with edible cloth -- produce has to be available at the drop of a hat if some piece needs replacing, and forethought is required about how the environment will impact their hard work.
To manage stress levels, Mercia went for something that's a little easier to predict -- all she has to do now is "wrangle" her model on the day.
"I'm using chocolate, because every woman loves chocolate -- it also means my garment is ready to go."
The talented designer is a great believer in the edible arts revolution, getting right behind what organisers are trying to achieve in Hawke's Bay.
"It's a good opportunity for people to put their creativity out there. Working to manipulate food or products is a stepping stone -- my daughter has used it and it's pushed her into the field of costume design."
WOW itself morphed from humble backyard beginnings in a Nelson tent to a stage show spectacle that attracts craftspeople, designers and artists from all over the globe. And yet it's very much a Kiwi institution. It celebrates our No8 wire creativity and often draws on New Zealand motifs and legends, while the open entry reflects our egalitarian culture.
"I'm not trained, it's just a passion for me, I can still be walked and showed up there alongside the professionals -- Kiwis have a different approach to design which keeps it interesting."
Mercia's Enarmoured, featuring aluminium koru-like tattoos, was her first piece to be showcased during the Air New Zealand South Pacific section of WOW in 2010.
The following year, Road Trip To ... placed third in the New Zealand Icon section, and is now on display at the museum in Nelson. 2012's creation Birth of Genus also took the stage.
Daughter Tessa, who's studying costume design in Wellington, is currently busy with a "top secret" edible outfit of her own.