CHICAGO — If a brand is bold enough to take down a category leader, it may as well be Butterfinger. That was Nestle U.S.A.’s rationale when it pitted its “crispety-crunchety, peanut buttery” candy bar against the country’s top-selling peanut butter cup: Hershey’s Reese’s brand. It took Nestle two years and many tests to develop Butterfinger Peanut Butter Cups, which launched in January, but the work has paid off, said Tricia Bowles, manager of division and brand affairs for Nestle Brands Co.’s confections and snacks division, in an interview with Food Business News at the Sweets & Snacks Expo held May 20-22 in Chicago.

“It has become the No. 1 launch in the history of Nestle U.S.A.’s confections and snacks division,” Ms. Bowles said. “And our Butterfinger base business is up 49% since January.”

No one at Nestle expected that kind of success, she said. The product has been selling faster than the company can make it.

The brand extension attracts new users, particularly those who may not like the messiness or mouthfeel of the original candy bar. The cups offer the Butterfinger taste but has a creamier texture with crunchy pieces mixed in. The product’s square shape brings a different look to the category, she added.

Other recent innovation from Nestle U.S.A. showcases the company’s whimsical side. Wonka Randoms feature a mash-up of shapes, textures and flavors to create rare combinations. The product includes 70 different shapes of traditional gummies, jam-filled gummies, and marshmallow-layered gummies, in seven flavors: grape, orange, strawberry, lemon, cherry, citrus and raspberry. The candies are made with fruit juice and no artificial colors or flavors.

“No bag is like any other bag,” Ms. Bowles said. “We actually did the math.”