27-year-old Middleton has plans to grow the Boomf concept - which prints Instagram and Facebook pictures on marshmallows - by opening a shop in New York.
Marshmallows with your face on them? We can definitely see that working Stateside.
CNNMoney reports Boomf has raised a cool £1 million so far thanks to investments from Nick Jenkins, founder of customised greetings card firm Moonpig, and other digital entrepreneurs.
A box of nine customised marshmallows costs £15 and can be made by simply uploading images from your camera roll, desktop, Instagram or Facebook page. As the Boomf website explains, it's "confectionery for the digital age."
It's a slick operation too - orders can be placed online and will be shipped out to customers within three days.
While James' former cake business (The Cake Kit Company) is still going, it's these "scrumptious, squishy, shareable" marshmallows that he's hoping to make it big with.
"Boomf has shipped over two tons of marshmallows in less than a year and made £100,000 ($168,000) in sales its first three months" reports CNNMoney.
Now that's a lot of marshmallows.
And what's the bet that these treats are handed out at every Middleton occasion? Here's a few shots from the Boomf Instagram page that prove James takes his magical little sweets everywhere he goes.
This is him and Pippa Middleton during their ride across the US...
MORE! Check out this gallery to see more from James' foodie sister Pippa...