Kate Middleton

Move over chocolates, cupcakes and macarons -- marshmallows are about to make a comeback! Kate Middleton's low-key younger brother, James Middleton, has a recently launched Boomf, a personalized marshmallow company. The 26-year-old businessman's latest venture allows consumers to order marshmallows with their edible Instagram pictures printed on top.

Middleton -- brother to the Duchess, 32, and Pippa, 30 -- has teamed up with Mint Digital to create the colorful treats, which can be shipped to consumers' doorsteps at $20 for a box of nine. Proudly showing off his business in new photos, Middleton, sporting a shaggy beard, stands next to a stack of Boomf packages while posing in a blazer, sweater and jeans. In another shot inside the warehouse, he wears a white chef apron and hat while holding out a marshmallow on display.

In an interview with The Next Web on Thursday, Jan. 23, Middleton, also the founder of cake company Nice Cakes, explained what he wanted to accomplish with his sweet new business. "I was working to three criteria: They had to be delicious, they had to fit though a letterbox (that is, not parcel-sized) and they could be [personalized]," he shared.

His idea for Boomf was borne out of an introduction to Mint in June of last year. "When I met Mint we clicked from the start," Middleton said. "We have a very similar vision but are coming at it from totally different angles: Mint from digital and me from food. I think the most fun we had was coming up with the name: Boomf is the noise a marshmallow makes when it falls through your letterbox."

The Duchess' brother -- who read the lesson inside Westminster Abbey at the royal wedding in April 2011 -- said he will continue to work on both Nice Cakes and Boomf.

"For the moment we are developing a 'Boomf on Demand' system so we will be able to create Boomf while you wait. We hope to use this at events and popups around the world. Also, we keep working on our BPM (that's Boomfs per minute) to reduce order turnaround time," he shared. "Our focus is to keep improving Boomf, and to cement our position as number one personalized marshmallow service worldwide."