"These are brigadeiros, a traditional sweet in Brazil," she explains.
The 34-year-old sells the delicacies through her business, My Sweet Brigadeiro. She launched it in 2011, a few months after moving to the Big Apple from Rio de Janeiro.
At the other end of the long, steel table from Ms Barbosa's brigadeiros is a completely different type of food preparation. Three women, led by Isabel Gunther, are tossing vegetables in with stringy, white rice noodles in large bowls.
These will be packaged for healthy school meals, part of Ms Gunther's business, Little Green Gourmets.
Both firms are renting space and facilities at a kitchen incubator called Hot Bread Kitchen (HBK), based in the East Harlem neighbourhood of Manhattan.
In a food-obsessed city, where alternative commercial space is expensive, such incubators are continuing to play a vital role in helping culinary start-ups get off the ground.
Since opening its doors in 2011, HBK has now assisted 100 small firms, who can also take advantage of business support.
Ms Barbosa sells most of her chocolates online, and in a few select food markets.
She was at one of those markets in 2011 when her brigadeiros got a favourable review from the New York Times. As a result, orders came flooding in.
"It was crazy - we were a fad and we weren't ready," says Ms Barbosa. "We didn't even have a credit card machine and we were saying 'yes' to everybody. So we decided to rent kitchen space and do this the proper way."
Today, she says orders remain strong. Her bestseller is a box of 30 brigadeiros, which retails for $52 (Â£34).
HBK is also a business in its own right, founded by Jessamyn Rodriguez. It employs 50 people working across a bakery business and the incubator section. Its breads are sold at Whole Foods and other retailers and markets in New York.
"We run a thriving, growing, 24-hour bakery business out of the same space," says Ms Rodriguez.
"And that's inspiring for entrepreneurs, to see this constant production and delivery schedule. They get the message that if all goes well, they could end up like this."
The HBK incubator charges a $500 annual fee for members, who can then rent kitchen space for $17 per hour, and access business counselling services on topics such as pricing structure and internet sales.
Entrepreneurs also get to network, which creates a collaborative community, says Ms Rodriguez.
Grace Moore, HBK's communications manager, adds that the incubator has a specific criteria for which food start-ups it accepts.
"We take in businesses with a proven idea, ready to grow," she says. "When they've been producing and selling for a year, and their kitchen at home is bursting at the seams, that's when we come in."
Michael Schwartz runs the Organic Food Incubator (OFI), based in Long Island City, in the New York borough of Queens.
He launched the centre in 2011 to provide food start-ups with the facilities and advice he struggled to find when he launched his own business, BAO Food and Drink.
"When we started BAO in 2009 we had endless trouble," says Mr Schwartz. "There was no-one to tell us how to get the product into a store, for example. The small food scene was very different [to how] it is now."
He adds that the OFI offers "everything from recipe development to making sure your label is legal".
The centre now incubates 60 companies, with prices starting from $220 for five days.
Like any traditional business incubator, it has its share of successful  graduates - entrepreneurs who have developed their start-up successfully and left the incubator to expand further.
Ariel Glazer's drinks company Kombrewcha spent its first two years at the OFI before recently moving production to a facility in New Hampshire.
The business makes a fermented tea with an alcohol level of 2%.
He credits the incubator with giving him the time and space to get the product right before its commercial release.
"When you start a business you don't know what you're getting into, and if you need lots more time to develop the product it can kill your business," says Mr Glazer. "By doing it through an incubator, you don't need to put up initial capital."
To be able to meet ever growing demand, both Mr Schwartz and Ms Rodriguez plan to expand their incubator facilities. Meanwhile, other food incubators are popping up all over the city.
Mr Schwartz credits the growing popularity of the local food movement - people wanting to buy food that is grown and produced locally.
Ms Rodriguez says the fact that New York's food lovers are always on the lookout for the next big thing also makes a difference.
"There are a lot of hungry mouths here who are trend-driven and looking for the newest thing coming to the market," she says.
In New York, small food start-ups are big business.
In a busy, communal kitchen in New York, Paula Barbosa is carefully placing little spheres of chocolate, coated in nuts, into individual sections in a gold box.