In November, just as she was about to open her second boutique in London, the jewelry designer Jessica McCormack welcomed the first client to the new “snug” in her flagship store.

The word is a traditional term for a small private room at a pub. But Ms. McCormack has been using it for the renovated workshop, where she has created what she sees as a different kind of jewelry retail experience: A way of putting craftsmanship front and center, in its rightful place “at the top of the food chain,” she said.

Since March 2015, when the designer installed a basement workshop in the Mayfair flagship, her team of craftspeople had grown from two to 14. And as she planned the second shop, in the Chelsea neighborhood, she knew more production space would be needed.

So this past fall, the original 596-square-foot workshop was expanded to 990 square feet. The space included a furnished viewing lounge, separated from the work area by a glass wall, where clients may watch the goldsmiths and setters at work.

Ms. McCormack likened the new area to a teppanyaki bar or open kitchen. “It’s where all the best, fun things happen,” she said in a phone interview from her native New Zealand during a holiday visit to her family.