Costco shoppers are flocking to the shelves over a legendary Aussie snack that has finally touched down in American stores. 

The “Australian Oreo” is sparking a wild Costco frenzy. Tim Tams, the iconic Australian cookie, have been stocked in Costco’s across the U.S. and American shoppers have been hoarding.

The Original Tim Tam is a triple-layered threat: two malted chocolate biscuits sandwiching a creamy cocoa filling, all covered in a thin layer of textured chocolate. While the classic is the gold standard, they also offer varieties like White Chocolate, Mangoes and Cream and Chocolate Mint.

At $13.99 a box, you get six sleeves — 66 cookies in total — but even that isn’t enough for the ravenous Costco crowds. Customers are loading up their carts with multiple boxes, creating a frenzy that is taking over the aisles.

The love for Tim Tams is not just about the taste, but the ritual. American customers are quickly learning the art of the “Tim Tam Slam.” As one Reddit user raved: “My Australian friend said to drink your coffee through them like a straw.”

The “Slam” is when you bite off diagonal corners, submerge one end in your hot beverage, and suck the liquid through the cookie like a straw. Once the hot coffee or tea melts the inner cream, you then eat the cookie before it dissolves. 

In Australia, where they were created by Arnott’s in 1964, the cookies are a national treasure. They are imported from Sydney and are known for the “Slam.”

The cookies being sold in the US are popular and still are not the original recipe as the AUS version. The box of Tim Tam available at Costco lists ingredients that include artificial color additives such as Red 40, Yellow 6, and Blue 1, which aren’t listed on the ingredient list for the Tim Tam cookies sold there.

The Tim Tam Slam craze has even reached celebs. Aussie actress Isla Fisher recently gave Kelly Clarkson a masterclass on the technique on the Kelly Clarkson Show. And Sarah Snook, Australian actress in Succession, also gave a tutorial to Jimmy Fallon when she was on the Tonight Show, the two dipping their Tim Tams in tea. 

The Tim Tam Slam trend reached virality on TikTok, with users sharing their “Aussie culture” and posting tutorials on how to properly do a “Slam.”

One Redditor bought 8-9 cases “because they’re the BEST store-bought cookie ever. I’m willing to die on that hill,” they wrote. Another said to Australian travelers: “Highly recommend a second suitcase so you can take back as many varieties as possible and get your friends hooked.” 

Costco is not only introducing international treasures, but also a new checkout system to improve customer experience, with new scanning technology and digital membership cards that have improved checkout speed up to 20%.