A milkshake featuring walnuts at Carl’s Jr. restaurants in Japan has been a summer smash.

The California Walnut Commission-affiliated promotion has been going on since July at the fast-food chain’s three restaurants in Tokyo and two in Kanagawa, and the drink has been selling so well that they’ve continued it through October.

The “Walnut Chocolate Banana Shake” is made with fresh bananas, chocolate and California walnuts, according to the commission. The promotion has resulted in record high sales in Carl’s Jr. Japan’s milkshake category, which prompted the company to continue the offering for an additional six weeks.

“Seasonal food and drink are a must in Japan, which means cold beverages gain a lot of attention during the summer,” the walnut commission stated in a release.

Since more than half of Carl’s Jr. customers in Japan are male, the company was looking to target female customers, in part with social-media promotions in collaboration with the CWC. The California Walnuts logo was featured on all the restaurant’s promotions and in-store materials.

“The promotion has successfully attracted female customers, resulting in an increase of this demographic on their social media channels,” the release stated.

Other countries

The promotion in Japan is one of numerous overseas projects the CWC is undertaking as part of its mission to develop export markets. In another, walnuts are among the American foods the USDA is promoting at AlMeera, the premier retail chain in Qatar.

The supermarket chain paid for the promotion, which included booths featuring promoters of American products. The walnut commission said the promotion reached thousands of consumers.

This summer, a partnership with the leading United Kingdom distributor Whitworth featured walnuts from the Golden State in a free-standing display. The display was up for 12 weeks in 780 Tesco stores, according to the commission.

The 200-gram packs of walnuts situated on the top two shelves in stores outsold weekly sales of Diet Coke early in the promotion, the organization reported.

Earlier this year, the walnut commission capitalized on a fascination with “ugly foods” in South Korea with a promotion of darker walnuts from last year’s crop.