The chef, who won the BBC show in 2012, launched the new restaurant with business partners Paul Brown and Ben McBean in March.
Piotrowski ended his seven-year tenure as chef patron at the Michelin-starred The Treby Arms in Sparkwell to open the new venture.
Now the team have gone their separate ways. Piotrowski wrote on Twitter: “I’m standing down as head chef @BrownAndBean. Thank you to each and every one of you who came down to taste my food.”
Brown & Bean has already appointed brothers Jimmy and Joe Cotton, who have worked at the restaurant since its opening, as joint head chefs.
“We have certainly enjoyed having Anton's input into our business however, from the outset, our true intention with Brown and Bean was always for it to be an establishment to give dynamic, talented young chefs their own opportunity to shine,” Brown told The Plymouth Herald.
Piotrowski has yet to confirm his next move, but told his Twitter followers to ‘watch this space’.