Ashton-Booth had previously been head chef at Martin Jarvis’ Stem restaurant in Mayfair, but stepped down from the role in April.
The restaurant closed less than two months later, little more than a year after it opened.
According to the Counter Culture Instagram page, Ashton-Booth will be introducing a new menu named The Allotment.
Sam’s love of veg and care for provenance on his plates sees him working closely with good friend Jake Ball on his allotment in Biggleswade, Bedfordshire,” it says.
“His menu at Counter Culture will be shaped by what is currently being harvested on Ball’s land.”
The full menu is yet to be confirmed, but dishes are set to include salt-baked red beetroot with pine and English strawberries; and raw beef with ‘allotment offerings’.
Before taking the reins at Stem, Ashton-Booth worked as head chef at Jarvis’ debut restaurant Anglo in Farringdon, and prior to that oversaw the kitchen at Tom Sellers' Restaurant Story in Southwark.
Counter Culture is the sibling to Gill’s The Dairy restaurant and opened in 2016.
Earlier this year Gill launched his latest concept Darby’s, a restaurant, oyster bar and bakery in London’s Embassy Gardens in Nine Elms.