The chef has partnered with the Darnley family, owners of the Estate on the rural Herefordshire-Worcestershire border, for the 46-cover project.
It comes after Westcott closed his well-regarded London restaurant, Bethnal Green’s Typing Room, in June.
Pensons will occupy a former derelict farm building, with an open kitchen and upstairs private dining room for 14 people.
It will offer both an a la carte and tasting menu based on the produce from the Estate, such as honey, cider, meat and game.
Sample dishes will include beef tongue, turnip, potato and onion; jerusalem artichoke, cod and truffle; and beetroot, chocolate and blackberry.
“Working with the seasons has always been of huge importance to how I approach my menus and working alongside the team of gardeners, farmers and the gamekeepers on the Estate will be very beneficial in continuing this approach,” says Westcott.
“The inspiration for us all is the countryside around the restaurant.”
Westcott previously worked at Restaurant Tom Aikens and oversaw two of Jason Atherton’s restaurant in Hong Kong. He also staged at Noma in Denmark and Per Se in New York.
The chef opened Typing Room, which was initially backed by Atherton, in 2014, and it was awarded four AA rosettes.