Burger King has added something you won’t get at McDonald’s, Wendy’s, or even Taco Bell.

Fast-food chains offer comfort food, but some never make it onto menus at McDonald’s (MCD) – Get McDonald’s Corporation Report, Restaurant Brands International’s (QSR) – Get Restaurant Brands International Inc Report Burger King or Wendy’s (WEN) – Get Wendy’s Company Report, or their nonburger rivals like Chipotle (CMG) – Get Chipotle Mexican Grill, Inc. Report and Yum Brands’  (YUM) – Get Yum! Brands, Inc. Report Taco Bell.

In some cases, that’s because well-liked items just never catch on. Hot dogs, for example, fit the fast-food model but have failed at both Burger King and McDonald’s. The same could be said for chicken wings, which have worked for fast-food chains built around them but not at traditional burger chains (largely due to price).

Onion rings, baked potatoes, mashed potatoes — these have all appeared on fast-food menus, but they’ve never been a big hit (although Wendy’s still has baked potatoes and Burger King sells onion rings).

In addition, some classic sandwiches have never worked in a fast-food setting. People love a grilled cheese or a good Cuban sandwich, but attempts to make these simple favorites into fast-food fare have either failed or not happened at all.

The most famous sandwich of all, however, the peanut butter and jelly, does not have a place on fast-food menus. That’s not changing, but Burger King has used one of its key ingredients on a line of new products it’s testing.

Burger King Makes Peanut Butter a Menu Item

Peanut butter seems like a no-go on U.S. menus, where peanut allergies have put the popular spread on the banned list at many schools. 

That may not be an issue in South Korea, where the fast-food giant has added peanut butter sauce to its menu. And while peanut butter sauce sounds like an ice cream topping (and it would probably be a delicious one), it’s not for the sweet side of the menu. It’s going on the savory side.

The chain has added multiple versions of its new Peanut Butter Stacker to its menu, albeit only in South Korea, Chewboom reported.

“The Peanut Butter Stacker features two of the brand’s signature grilled beef patties layered mayo, pickles, American cheese, and a new peanut butter sauce made with creamy peanut butter and brown cheese all sandwich between a sesame seed bun,” the website reported. 

“It’s also available as a Peanut Butter Beef & Chicken Stacker, made with all the same ingredients as the Peanut Butter Stacker (minus the cheese), but instead of two beef patties, it comes with one beef patty and a crispy chicken patty.”

Just having a sandwich with a beef and a fried chicken patty counts as novel, but adding peanut butter sauce makes it extra indulgent. Burger King also offers Peanut Butter Fries. The whole new menu will be available through May 7, 2022.

Peanut Butter Burgers Sort of Make Sense

Peanut sauce has been a staple of Thai cuisine and it’s used in some South Korean cooking. It may not be a classic burger topping, but it’s not exactly a big stretch to go from a peanut butter and jelly sandwich to a hamburger with a peanut butter topping.

The oddest piece of this may actually not be the peanut butter, but the fact that the sauce also includes cheese — not a typical mixer with peanut butter.

Still, something unique might work in this market and it could then be rolled out in other Burger King territories (although it seems unlikely in the U.S). The attempt here isn’t just to get attention. It’s to find something new that customers really want to try.

For Burger King’s current customers, a novel new product might lead to higher check averages and a better chance that a regular might spread word of mouth about the new items. That could bring more customers in.