Denheath Desserts in Timaru wants the public to pitch in and help them build a bigger factory to meet overseas demand for their custard squares.
Co-owner Lisa Templeton's parents bought Denheath Desserts in 1996 just so they could get their hands on the secret recipe behind the custard squares.
Ms Templeton, who worked for the small business after school as a 15-year-old, said she always knew her mother wanted to buy the dessert place.
"She was the one that was really keen. Mum and Dad bought Denheath [because] they wanted the custard square."
They haven't changed the recipe in the 20 years since. Ms Templeton says their custard squares are light and fluffy, and not too sweet.
"It's not like normal custard square - it's much more gourmet."
Her mother, who died in 2000, had the dream to take the Denheath custard squares international.
Their factory in Timaru already produces more than 10,000 squares a day, but Ms Templeton says they need $1.2 million so they can make enough to export.
"We just want more capacity in our factory so that we can produce more," she says.
But they ran into a small problem with the international market.
"We've had to introduce different sizes because [the international market] don't understand the big boys," she says. "When we turned it into a slice, it was much more acceptable overseas."
The crowdfunding campaign to expand the factory begins on October 31.