Portillo's has brought back its lemon cake until July 31. View Full Caption Courtesy Portillo's

DOWNTOWN — Chicago has a new star: Portillo's lemon cake.

The cake — which has been brought back after a decadelong absence — was used to open "Jimmy Kimmel Live" on Tuesday night. The late night show's opening was filmed at Portillo's, 520 W. Taylor St., and featured the restaurant's employees bouncing and smiling while holding lemon cake (and hot dogs, of course).

"After 10 long years, we're bringing back our famous Pooooortillo's lemon cake," a Portillo's employee told the audience. "So come on down and get a slice right after we start the shooooow!"

The temporary return of the cake has gained national attention — and so has the reason it came back: A diehard fan from West Lawn, Ben, searched for the cake or a similar recipe for 10 years. He finally offered a $300 bounty for a slice in an online post, and Portillo's responded by making him a cake and giving him the recipe.

Ben's bounty proved so popular online that people sent thousands of messages to Portillo's and Ben asking for the recipe. Portillo's agreed to bring the cake back June 13-July 31.

Check out the cake's appearance:

The return has proved popular among Portillo's fans.

"Portillo's and their lemon cake is the love of my life," one person wrote on Twitter after getting a slice last week.

"Portillo's lemon cake tastes like sunshine and happiness," another wrote.

"Portillo's lemon cake is everything I'd hoped," wrote yet another fan. She added, "It's just the perfect cake, perfect frosting."

Now, Ben — and other fans — are hoping Portillo's will bring back the cake permanently. A spokeswoman for Portillo's, Ana Espinoza, said the restaurant has no plans to do that for now, but anything could happen in the future.

"It just shows, really, what people can accomplish if they get together and stand up," Ben told DNAinfo last month. "I'm just so happy that everyone who wanted [the cake] ... they'll have their chance.

Portillo's brought back its famed lemon cake after a diehard fan offered a $300 bounty for a slice, sparking an internet campaign for the dessert's return. View Full Caption Courtesy Portillo's

"I'm hoping it's gonna sell out and Portillo's" will bring back the cake permanently, he said.

Ben, who grew up in West Lawn, first tried the cake while a kid going to Portillo's with his dad. The two are no fans of chocolate and would drive 30-40 minutes to the Portillo's at least one a month for the treat. It became a special event for the two, and Ben even ended up hosting his high school graduation party at Portillo's — with a lemon cake.

"I fell in love with the lemon cake absolutely from the first time I saw it," Ben said, laughing.

A little less than a decade ago Portillo's stopped serving the cake. Ben tried for years to find one that tasted similar and, even though he's no baker, he turned to his own kitchen tried at least 20 recipes in hopes of finding one that could mimic the lemon cake. Recipe after recipe failed to hold up.

That's when Ben grew desperate enough to offer a bounty on the internet: $300 for the recipe or a copycat cake, plus $30 if you could find out why the cake went missing from the restaurants. (He thought $300 was "absolutely worth it," he said, and wanted to make sure the bounty was high enough that it'd get people searching for a recipe.)

Luckily for him, Portillo's stepped in, offering to "make your dream come true" by giving Ben a lemon cake and telling him how to make it.

It was after that, that thousands began reaching out to Portillo's asking for their own response, prompting the restaurant to temporarily bring back the cake.

Read more:

• Portillo's Is Bringing Back Lemon Cake After Die-Hard Fan's Campaign

• The Guy Who Is In Love With Portillo's Lemon Cake FINALLY Got A Slice

• Man Misses Portillo's Lemon Cake So Much He Offers $300 Bounty For It